String
class String : Serializable, Comparable<String!>, CharSequence
kotlin.Any | |
↳ | java.lang.String |
The String
class represents character strings. All string literals in Java programs, such as "abc"
, are implemented as instances of this class.
Strings are constant; their values cannot be changed after they are created. String buffers support mutable strings. Because String objects are immutable they can be shared. For example:
String str = "abc";
is equivalent to:
char data[] = {'a', 'b', 'c'}; String str = new String(data);
Here are some more examples of how strings can be used:
System.out.println("abc"); String cde = "cde"; System.out.println("abc" + cde); String c = "abc".substring(2,3); String d = cde.substring(1, 2);
The class String
includes methods for examining individual characters of the sequence, for comparing strings, for searching strings, for extracting substrings, and for creating a copy of a string with all characters translated to uppercase or to lowercase. Case mapping is based on the Unicode Standard version specified by the Character
class.
The Java language provides special support for the string concatenation operator ( + ), and for conversion of other objects to strings. For additional information on string concatenation and conversion, see The Java™ Language Specification.
Unless otherwise noted, passing a null
argument to a constructor or method in this class will cause a NullPointerException
to be thrown.
A String
represents a string in the UTF-16 format in which supplementary characters are represented by surrogate pairs (see the section Unicode Character Representations in the Character
class for more information). Index values refer to char
code units, so a supplementary character uses two positions in a String
.
The String
class provides methods for dealing with Unicode code points (i.e., characters), in addition to those for dealing with Unicode code units (i.e., char
values).
Unless otherwise noted, methods for comparing Strings do not take locale into account. The java.text.Collator
class provides methods for finer-grain, locale-sensitive String comparison.
Summary
Public constructors | |
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String() Initializes a newly created |
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Initializes a newly created |
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Allocates a new |
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Allocates a new |
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Allocates a new |
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Allocates a new |
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Allocates a new |
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Constructs a new |
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Constructs a new |
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Constructs a new |
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Constructs a new |
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Constructs a new |
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String(buffer: StringBuffer) Allocates a new string that contains the sequence of characters currently contained in the string buffer argument. |
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String(builder: StringBuilder) Allocates a new string that contains the sequence of characters currently contained in the string builder argument. |
Public methods | |
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IntStream |
chars() Returns a stream of |
Int |
codePointAt(index: Int) Returns the character (Unicode code point) at the specified index. |
Int |
codePointBefore(index: Int) Returns the character (Unicode code point) before the specified index. |
Int |
codePointCount(beginIndex: Int, endIndex: Int) Returns the number of Unicode code points in the specified text range of this |
IntStream |
Returns a stream of code point values from this sequence. |
Int |
Compares two strings lexicographically. |
Int |
compareToIgnoreCase(str: String) Compares two strings lexicographically, ignoring case differences. |
String |
Concatenates the specified string to the end of this string. |
Boolean |
contains(s: CharSequence) Returns true if and only if this string contains the specified sequence of char values. |
Boolean |
Compares this string to the specified |
Boolean |
Compares this string to the specified |
static String |
copyValueOf(data: CharArray!, offset: Int, count: Int) Equivalent to |
static String |
copyValueOf(data: CharArray!) Equivalent to |
Boolean |
Tests if this string ends with the specified suffix. |
Boolean |
Compares this string to the specified object. |
Boolean |
equalsIgnoreCase(anotherString: String?) Compares this |
static String |
Returns a formatted string using the specified format string and arguments. |
static String |
Returns a formatted string using the specified locale, format string, and arguments. |
String |
Formats using this string as the format string, and the supplied arguments. |
Char |
Returns the |
Unit |
Copies characters from this string into the destination byte array. |
ByteArray! |
Encodes this |
ByteArray! |
Encodes this |
ByteArray! |
getBytes() Encodes this |
Unit |
Copies characters from this string into the destination character array. |
Int |
hashCode() Returns a hash code for this string. |
String |
Adjusts the indentation of each line of this string based on the value of |
Int |
Returns the index within this string of the first occurrence of the specified character. |
Int |
Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index. |
Int |
Returns the index within this string of the first occurrence of the specified substring. |
Int |
Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. |
String |
intern() Returns a canonical representation for the string object. |
Boolean |
isBlank() Returns |
Boolean |
isEmpty() Returns |
static String |
join(delimiter: CharSequence, vararg elements: CharSequence!) Returns a new String composed of copies of the |
static String |
join(delimiter: CharSequence, elements: MutableIterable<CharSequence!>) Returns a new |
Int |
lastIndexOf(ch: Int) Returns the index within this string of the last occurrence of the specified character. |
Int |
lastIndexOf(ch: Int, fromIndex: Int) Returns the index within this string of the last occurrence of the specified character, searching backward starting at the specified index. |
Int |
lastIndexOf(str: String) Returns the index within this string of the last occurrence of the specified substring. |
Int |
lastIndexOf(str: String, fromIndex: Int) Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index. |
Stream<String!> |
lines() Returns a stream of lines extracted from this string, separated by line terminators. |
Boolean |
Tells whether or not this string matches the given regular expression. |
Int |
offsetByCodePoints(index: Int, codePointOffset: Int) Returns the index within this |
Boolean |
regionMatches(toffset: Int, other: String, ooffset: Int, len: Int) Tests if two string regions are equal. |
Boolean |
Tests if two string regions are equal. |
String |
Returns a string whose value is the concatenation of this string repeated |
String |
Returns a string resulting from replacing all occurrences of |
String |
replace(target: CharSequence, replacement: CharSequence) Replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence. |
String |
replaceAll(regex: String, replacement: String) Replaces each substring of this string that matches the given regular expression with the given replacement. |
String |
replaceFirst(regex: String, replacement: String) Replaces the first substring of this string that matches the given regular expression with the given replacement. |
Array<String!> |
Splits this string around matches of the given regular expression. |
Array<String!> |
Splits this string around matches of the given regular expression. |
Boolean |
startsWith(prefix: String, toffset: Int) Tests if the substring of this string beginning at the specified index starts with the specified prefix. |
Boolean |
startsWith(prefix: String) Tests if this string starts with the specified prefix. |
String |
strip() Returns a string whose value is this string, with all leading and trailing |
String |
Returns a string whose value is this string, with incidental removed from the beginning and end of every line. |
String |
Returns a string whose value is this string, with all leading |
String |
Returns a string whose value is this string, with all trailing |
CharSequence |
subSequence(startIndex: Int, endIndex: Int) Returns a character sequence that is a subsequence of this sequence. |
String |
Returns a string that is a substring of this string. |
String |
Returns a string that is a substring of this string. |
CharArray! |
Converts this string to a new character array. |
String |
toLowerCase(locale: Locale) Converts all of the characters in this |
String |
Converts all of the characters in this |
String |
toString() This object (which is already a string!) is itself returned. |
String |
toUpperCase(locale: Locale) Converts all of the characters in this |
String |
Converts all of the characters in this |
R |
This method allows the application of a function to |
String |
Returns a string whose value is this string, with escape sequences translated as if in a string literal. |
String |
trim() Returns a string whose value is this string, with all leading and trailing space removed, where space is defined as any character whose codepoint is less than or equal to |
static String |
Returns the string representation of the |
static String |
Returns the string representation of the |
static String |
Returns the string representation of a specific subarray of the |
static String |
Returns the string representation of the |
static String |
Returns the string representation of the |
static String |
Returns the string representation of the |
static String |
Returns the string representation of the |
static String |
Returns the string representation of the |
static String |
Returns the string representation of the |
Properties | |
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static Comparator<String!>! |
A Comparator that orders |
Int |
Returns the length of this string. |
Public constructors
String
String()
Initializes a newly created String
object so that it represents an empty character sequence. Note that use of this constructor is unnecessary since Strings are immutable.
String
String(original: String)
Initializes a newly created String
object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string. Unless an explicit copy of original
is needed, use of this constructor is unnecessary since Strings are immutable.
Parameters | |
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original |
String: A String |
String
String(value: CharArray!)
Allocates a new String
so that it represents the sequence of characters currently contained in the character array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string.
Parameters | |
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value |
CharArray!: The initial value of the string |
String
String(
value: CharArray!,
offset: Int,
count: Int)
Allocates a new String
that contains characters from a subarray of the character array argument. The offset
argument is the index of the first character of the subarray and the count
argument specifies the length of the subarray. The contents of the subarray are copied; subsequent modification of the character array does not affect the newly created string.
Parameters | |
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value |
CharArray!: Array that is the source of characters |
offset |
Int: The initial offset |
count |
Int: The length |
Exceptions | |
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java.lang.IndexOutOfBoundsException |
If offset is negative, count is negative, or offset is greater than value.length - count |
String
String(
codePoints: IntArray!,
offset: Int,
count: Int)
Allocates a new String
that contains characters from a subarray of the Unicode code point array argument. The offset
argument is the index of the first code point of the subarray and the count
argument specifies the length of the subarray. The contents of the subarray are converted to char
s; subsequent modification of the int
array does not affect the newly created string.
Parameters | |
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codePoints |
IntArray!: Array that is the source of Unicode code points |
offset |
Int: The initial offset |
count |
Int: The length |
Exceptions | |
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java.lang.IllegalArgumentException |
If any invalid Unicode code point is found in codePoints |
java.lang.IndexOutOfBoundsException |
If offset is negative, count is negative, or offset is greater than codePoints.length - count |
String
String(
ascii: ByteArray!,
hibyte: Int,
offset: Int,
count: Int)
Deprecated: This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String
constructors that take a , charset name, or that use the platform's default charset.
Allocates a new String
constructed from a subarray of an array of 8-bit integer values.
The offset
argument is the index of the first byte of the subarray, and the count
argument specifies the length of the subarray.
Each byte
in the subarray is converted to a char
as specified in the String(byte[],int)
constructor.
Parameters | |
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ascii |
ByteArray!: The bytes to be converted to characters |
hibyte |
Int: The top 8 bits of each 16-bit Unicode code unit |
offset |
Int: The initial offset |
count |
Int: The length |
Exceptions | |
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java.lang.IndexOutOfBoundsException |
If offset is negative, count is negative, or offset is greater than ascii.length - count |
String
String(
ascii: ByteArray!,
hibyte: Int)
Deprecated: This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String
constructors that take a , charset name, or that use the platform's default charset.
Allocates a new String
containing characters constructed from an array of 8-bit integer values. Each character c in the resulting string is constructed from the corresponding component b in the byte array such that:
<b><i>c</i></b>== (char)(((hibyte & 0xff) << 8) | (<b><i>b</i></b>& 0xff))
Parameters | |
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ascii |
ByteArray!: The bytes to be converted to characters |
hibyte |
Int: The top 8 bits of each 16-bit Unicode code unit |
String
String(
bytes: ByteArray!,
offset: Int,
length: Int,
charsetName: String)
String
String(
bytes: ByteArray!,
offset: Int,
length: Int,
charset: Charset)
Constructs a new String
by decoding the specified subarray of bytes using the specified charset. The length of the new String
is a function of the charset, and hence may not be equal to the length of the subarray.
This method always replaces malformed-input and unmappable-character sequences with this charset's default replacement string. The class should be used when more control over the decoding process is required.
Parameters | |
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bytes |
ByteArray!: The bytes to be decoded into characters |
offset |
Int: The index of the first byte to decode |
length |
Int: The number of bytes to decode |
charset |
Charset: The charset to be used to decode the bytes |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
If offset is negative, length is negative, or offset is greater than bytes.length - length |
String
String(
bytes: ByteArray!,
charsetName: String)
Constructs a new String
by decoding the specified array of bytes using the specified charset. The length of the new String
is a function of the charset, and hence may not be equal to the length of the byte array.
The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. The class should be used when more control over the decoding process is required.
Parameters | |
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bytes |
ByteArray!: The bytes to be decoded into characters |
charsetName |
String: The name of a supported charset |
Exceptions | |
---|---|
java.io.UnsupportedEncodingException |
If the named charset is not supported |
String
String(
bytes: ByteArray!,
charset: Charset)
Constructs a new String
by decoding the specified array of bytes using the specified charset. The length of the new String
is a function of the charset, and hence may not be equal to the length of the byte array.
This method always replaces malformed-input and unmappable-character sequences with this charset's default replacement string. The class should be used when more control over the decoding process is required.
Parameters | |
---|---|
bytes |
ByteArray!: The bytes to be decoded into characters |
charset |
Charset: The charset to be used to decode the bytes |
String
String(
bytes: ByteArray!,
offset: Int,
length: Int)
Constructs a new String
by decoding the specified subarray of bytes using the platform's default charset. The length of the new String
is a function of the charset, and hence may not be equal to the length of the subarray.
The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The class should be used when more control over the decoding process is required.
Parameters | |
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bytes |
ByteArray!: The bytes to be decoded into characters |
offset |
Int: The index of the first byte to decode |
length |
Int: The number of bytes to decode |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
If offset is negative, length is negative, or offset is greater than bytes.length - length |
String
String(bytes: ByteArray!)
Constructs a new String
by decoding the specified array of bytes using the platform's default charset. The length of the new String
is a function of the charset, and hence may not be equal to the length of the byte array.
The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The class should be used when more control over the decoding process is required.
Parameters | |
---|---|
bytes |
ByteArray!: The bytes to be decoded into characters |
String
String(buffer: StringBuffer)
Allocates a new string that contains the sequence of characters currently contained in the string buffer argument. The contents of the string buffer are copied; subsequent modification of the string buffer does not affect the newly created string.
Parameters | |
---|---|
buffer |
StringBuffer: A StringBuffer |
String
String(builder: StringBuilder)
Allocates a new string that contains the sequence of characters currently contained in the string builder argument. The contents of the string builder are copied; subsequent modification of the string builder does not affect the newly created string.
This constructor is provided to ease migration to StringBuilder
. Obtaining a string from a string builder via the toString
method is likely to run faster and is generally preferred.
Parameters | |
---|---|
builder |
StringBuilder: A StringBuilder |
Public methods
chars
fun chars(): IntStream
Returns a stream of int
zero-extending the char
values from this sequence. Any char which maps to a surrogate code point is passed through uninterpreted.
Return | |
---|---|
IntStream |
an IntStream of char values from this sequence |
codePointAt
fun codePointAt(index: Int): Int
Returns the character (Unicode code point) at the specified index. The index refers to char
values (Unicode code units) and ranges from 0
to length()
- 1
.
If the char
value specified at the given index is in the high-surrogate range, the following index is less than the length of this String
, and the char
value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char
value at the given index is returned.
Parameters | |
---|---|
index |
Int: the index to the char values |
Return | |
---|---|
Int |
the code point value of the character at the index |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if the index argument is negative or not less than the length of this string. |
codePointBefore
fun codePointBefore(index: Int): Int
Returns the character (Unicode code point) before the specified index. The index refers to char
values (Unicode code units) and ranges from 1
to length
.
If the char
value at (index - 1)
is in the low-surrogate range, (index - 2)
is not negative, and the char
value at (index - 2)
is in the high-surrogate range, then the supplementary code point value of the surrogate pair is returned. If the char
value at index - 1
is an unpaired low-surrogate or a high-surrogate, the surrogate value is returned.
Parameters | |
---|---|
index |
Int: the index following the code point that should be returned |
Return | |
---|---|
Int |
the Unicode code point value before the given index. |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if the index argument is less than 1 or greater than the length of this string. |
codePointCount
fun codePointCount(
beginIndex: Int,
endIndex: Int
): Int
Returns the number of Unicode code points in the specified text range of this String
. The text range begins at the specified beginIndex
and extends to the char
at index endIndex - 1
. Thus the length (in char
s) of the text range is endIndex-beginIndex
. Unpaired surrogates within the text range count as one code point each.
Parameters | |
---|---|
beginIndex |
Int: the index to the first char of the text range. |
endIndex |
Int: the index after the last char of the text range. |
Return | |
---|---|
Int |
the number of Unicode code points in the specified text range |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if the beginIndex is negative, or endIndex is larger than the length of this String , or beginIndex is larger than endIndex . |
codePoints
fun codePoints(): IntStream
Returns a stream of code point values from this sequence. Any surrogate pairs encountered in the sequence are combined as if by Character.toCodePoint and the result is passed to the stream. Any other code units, including ordinary BMP characters, unpaired surrogates, and undefined code units, are zero-extended to int
values which are then passed to the stream.
Return | |
---|---|
IntStream |
an IntStream of Unicode code points from this sequence |
compareTo
fun compareTo(other: String): Int
Compares two strings lexicographically. The comparison is based on the Unicode value of each character in the strings. The character sequence represented by this String
object is compared lexicographically to the character sequence represented by the argument string. The result is a negative integer if this String
object lexicographically precedes the argument string. The result is a positive integer if this String
object lexicographically follows the argument string. The result is zero if the strings are equal; returns 0
exactly when the equals(java.lang.Object)
method would return true
.
This is the definition of lexicographic ordering. If two strings are different, then either they have different characters at some index that is a valid index for both strings, or their lengths are different, or both. If they have different characters at one or more index positions, let k be the smallest such index; then the string whose character at position k has the smaller value, as determined by using the <
operator, lexicographically precedes the other string. In this case, compareTo
returns the difference of the two character values at position k
in the two string -- that is, the value:
this.charAt(k)-anotherString.charAt(k)
compareTo
returns the difference of the lengths of the strings -- that is, the value:
this.length()-anotherString.length()
For finer-grained String comparison, refer to java.text.Collator
.
Parameters | |
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o |
the object to be compared. |
anotherString |
the String to be compared. |
Return | |
---|---|
Int |
the value 0 if the argument string is equal to this string; a value less than 0 if this string is lexicographically less than the string argument; and a value greater than 0 if this string is lexicographically greater than the string argument. |
Exceptions | |
---|---|
java.lang.NullPointerException |
if the specified object is null |
java.lang.ClassCastException |
if the specified object's type prevents it from being compared to this object. |
compareToIgnoreCase
fun compareToIgnoreCase(str: String): Int
Compares two strings lexicographically, ignoring case differences. This method returns an integer whose sign is that of calling compareTo
with normalized versions of the strings where case differences have been eliminated by calling Character.toLowerCase(Character.toUpperCase(character))
on each character.
Note that this method does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The java.text.Collator
class provides locale-sensitive comparison.
Parameters | |
---|---|
str |
String: the String to be compared. |
Return | |
---|---|
Int |
a negative integer, zero, or a positive integer as the specified String is greater than, equal to, or less than this String, ignoring case considerations. |
See Also
concat
fun concat(str: String): String
Concatenates the specified string to the end of this string.
If the length of the argument string is 0
, then this String
object is returned. Otherwise, a String
object is returned that represents a character sequence that is the concatenation of the character sequence represented by this String
object and the character sequence represented by the argument string.
Examples:
"cares".concat("s") returns "caress" "to".concat("get").concat("her") returns "together"
Parameters | |
---|---|
str |
String: the String that is concatenated to the end of this String . |
Return | |
---|---|
String |
a string that represents the concatenation of this object's characters followed by the string argument's characters. |
contains
fun contains(s: CharSequence): Boolean
Returns true if and only if this string contains the specified sequence of char values.
Parameters | |
---|---|
s |
CharSequence: the sequence to search for |
Return | |
---|---|
Boolean |
true if this string contains s , false otherwise |
contentEquals
fun contentEquals(sb: StringBuffer): Boolean
Compares this string to the specified StringBuffer
. The result is true
if and only if this String
represents the same sequence of characters as the specified StringBuffer
. This method synchronizes on the StringBuffer
.
For finer-grained String comparison, refer to java.text.Collator
.
Parameters | |
---|---|
sb |
StringBuffer: The StringBuffer to compare this String against |
Return | |
---|---|
Boolean |
true if this String represents the same sequence of characters as the specified StringBuffer , false otherwise |
contentEquals
fun contentEquals(cs: CharSequence): Boolean
Compares this string to the specified CharSequence
. The result is true
if and only if this String
represents the same sequence of char values as the specified sequence. Note that if the CharSequence
is a StringBuffer
then the method synchronizes on it.
For finer-grained String comparison, refer to java.text.Collator
.
Parameters | |
---|---|
cs |
CharSequence: The sequence to compare this String against |
Return | |
---|---|
Boolean |
true if this String represents the same sequence of char values as the specified sequence, false otherwise |
copyValueOf
static fun copyValueOf(
data: CharArray!,
offset: Int,
count: Int
): String
Equivalent to valueOf(char[],int,int)
.
Parameters | |
---|---|
data |
CharArray!: the character array. |
offset |
Int: initial offset of the subarray. |
count |
Int: length of the subarray. |
Return | |
---|---|
String |
a String that contains the characters of the specified subarray of the character array. |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if offset is negative, or count is negative, or offset+count is larger than data.length . |
copyValueOf
static fun copyValueOf(data: CharArray!): String
Equivalent to valueOf(char[])
.
Parameters | |
---|---|
data |
CharArray!: the character array. |
Return | |
---|---|
String |
a String that contains the characters of the character array. |
endsWith
fun endsWith(suffix: String): Boolean
Tests if this string ends with the specified suffix.
Parameters | |
---|---|
suffix |
String: the suffix. |
Return | |
---|---|
Boolean |
true if the character sequence represented by the argument is a suffix of the character sequence represented by this object; false otherwise. Note that the result will be true if the argument is the empty string or is equal to this String object as determined by the equals(java.lang.Object) method. |
equals
fun equals(other: Any?): Boolean
Compares this string to the specified object. The result is true
if and only if the argument is not null
and is a String
object that represents the same sequence of characters as this object.
For finer-grained String comparison, refer to java.text.Collator
.
Parameters | |
---|---|
obj |
the reference object with which to compare. |
anObject |
The object to compare this String against |
Return | |
---|---|
Boolean |
true if the given object represents a String equivalent to this string, false otherwise |
equalsIgnoreCase
fun equalsIgnoreCase(anotherString: String?): Boolean
Compares this String
to another String
, ignoring case considerations. Two strings are considered equal ignoring case if they are of the same length and corresponding characters in the two strings are equal ignoring case.
Two characters c1
and c2
are considered the same ignoring case if at least one of the following is true:
- The two characters are the same (as compared by the
==
operator) - Calling
Character.toLowerCase(Character.toUpperCase(char))
on each character produces the same result
Note that this method does not take locale into account, and will result in unsatisfactory results for certain locales. The java.text.Collator
class provides locale-sensitive comparison.
Parameters | |
---|---|
anotherString |
String?: The String to compare this String against |
Return | |
---|---|
Boolean |
true if the argument is not null and it represents an equivalent String ignoring case; false otherwise |
See Also
format
static fun format(
format: String,
vararg args: Any!
): String
Returns a formatted string using the specified format string and arguments.
The locale always used is the one returned by Locale.getDefault(Locale.Category)
with FORMAT
category specified.
Parameters | |
---|---|
format |
String: A format string |
args |
Any!: Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion. |
Return | |
---|---|
String |
A formatted string |
Exceptions | |
---|---|
java.util.IllegalFormatException |
If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification. |
See Also
format
static fun format(
l: Locale,
format: String,
vararg args: Any!
): String
Returns a formatted string using the specified locale, format string, and arguments.
Parameters | |
---|---|
l |
Locale: The locale to apply during formatting. If l is null then no localization is applied. |
format |
String: A format string |
args |
Any!: Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion. |
Return | |
---|---|
String |
A formatted string |
Exceptions | |
---|---|
java.util.IllegalFormatException |
If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification |
See Also
formatted
fun formatted(vararg args: Any!): String
Formats using this string as the format string, and the supplied arguments.
Parameters | |
---|---|
args |
Any!: Arguments referenced by the format specifiers in this string. |
Return | |
---|---|
String |
A formatted string |
get
fun get(index: Int): Char
Returns the char
value at the specified index. An index ranges from 0
to length() - 1
. The first char
value of the sequence is at index 0
, the next at index 1
, and so on, as for array indexing.
If the char
value specified by the index is a surrogate, the surrogate value is returned.
Parameters | |
---|---|
index |
Int: the index of the char value. |
Return | |
---|---|
Char |
the char value at the specified index of this string. The first char value is at index 0 . |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if the index argument is negative or not less than length() |
java.lang.IndexOutOfBoundsException |
if the index argument is negative or not less than the length of this string. |
getBytes
fungetBytes(
srcBegin: Int,
srcEnd: Int,
dst: ByteArray!,
dstBegin: Int
): Unit
Deprecated: This method does not properly convert characters into bytes. As of JDK 1.1, the preferred way to do this is via the getBytes()
method, which uses the platform's default charset.
Copies characters from this string into the destination byte array. Each byte receives the 8 low-order bits of the corresponding character. The eight high-order bits of each character are not copied and do not participate in the transfer in any way.
The first character to be copied is at index srcBegin
; the last character to be copied is at index srcEnd-1
. The total number of characters to be copied is srcEnd-srcBegin
. The characters, converted to bytes, are copied into the subarray of dst
starting at index dstBegin
and ending at index:
dstBegin + (srcEnd-srcBegin) - 1
Parameters | |
---|---|
srcBegin |
Int: Index of the first character in the string to copy |
srcEnd |
Int: Index after the last character in the string to copy |
dst |
ByteArray!: The destination array |
dstBegin |
Int: The start offset in the destination array |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
If any of the following is true:
|
getBytes
fun getBytes(charsetName: String): ByteArray!
Encodes this String
into a sequence of bytes using the named charset, storing the result into a new byte array.
The behavior of this method when this string cannot be encoded in the given charset is unspecified. The class should be used when more control over the encoding process is required.
Parameters | |
---|---|
charsetName |
String: The name of a supported charset |
Return | |
---|---|
ByteArray! |
The resultant byte array |
Exceptions | |
---|---|
java.io.UnsupportedEncodingException |
If the named charset is not supported |
getBytes
fun getBytes(charset: Charset): ByteArray!
Encodes this String
into a sequence of bytes using the given charset, storing the result into a new byte array.
This method always replaces malformed-input and unmappable-character sequences with this charset's default replacement byte array. The java.nio.charset.CharsetEncoder
class should be used when more control over the encoding process is required.
Parameters | |
---|---|
charset |
Charset: The java.nio.charset.Charset to be used to encode the String |
Return | |
---|---|
ByteArray! |
The resultant byte array |
getBytes
fun getBytes(): ByteArray!
Encodes this String
into a sequence of bytes using the platform's default charset, storing the result into a new byte array.
The behavior of this method when this string cannot be encoded in the default charset is unspecified. The class should be used when more control over the encoding process is required.
Return | |
---|---|
ByteArray! |
The resultant byte array |
getChars
fun getChars(
srcBegin: Int,
srcEnd: Int,
dst: CharArray!,
dstBegin: Int
): Unit
Copies characters from this string into the destination character array.
The first character to be copied is at index srcBegin
; the last character to be copied is at index srcEnd-1
(thus the total number of characters to be copied is srcEnd-srcBegin
). The characters are copied into the subarray of dst
starting at index dstBegin
and ending at index:
dstBegin + (srcEnd-srcBegin) - 1
Parameters | |
---|---|
srcBegin |
Int: index of the first character in the string to copy. |
srcEnd |
Int: index after the last character in the string to copy. |
dst |
CharArray!: the destination array. |
dstBegin |
Int: the start offset in the destination array. |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
If any of the following is true:
|
hashCode
fun hashCode(): Int
Returns a hash code for this string. The hash code for a String
object is computed as
s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
int
arithmetic, where s[i]
is the ith character of the string, n
is the length of the string, and ^
indicates exponentiation. (The hash value of the empty string is zero.)
Return | |
---|---|
Int |
a hash code value for this object. |
indent
fun indent(n: Int): String
Adjusts the indentation of each line of this string based on the value of n
, and normalizes line termination characters.
This string is conceptually separated into lines using String#lines()
. Each line is then adjusted as described below and then suffixed with a line feed "\n"
(U+000A). The resulting lines are then concatenated and returned.
If n > 0
then n
spaces (U+0020) are inserted at the beginning of each line.
If n < 0
then up to n
white space characters are removed from the beginning of each line. If a given line does not contain sufficient white space then all leading white space characters are removed. Each white space character is treated as a single character. In particular, the tab character "\t"
(U+0009) is considered a single character; it is not expanded.
If n == 0
then the line remains unchanged. However, line terminators are still normalized.
Parameters | |
---|---|
n |
Int: number of leading white space characters to add or remove |
Return | |
---|---|
String |
string with indentation adjusted and line endings normalized |
indexOf
fun indexOf(ch: Int): Int
Returns the index within this string of the first occurrence of the specified character. If a character with value ch
occurs in the character sequence represented by this String
object, then the index (in Unicode code units) of the first such occurrence is returned. For values of ch
in the range from 0 to 0xFFFF (inclusive), this is the smallest value k such that:
this.charAt(<i>k</i>) == ch
ch
, it is the smallest value k such that:
this.codePointAt(<i>k</i>) == ch
-1
is returned.
Parameters | |
---|---|
ch |
Int: a character (Unicode code point). |
Return | |
---|---|
Int |
the index of the first occurrence of the character in the character sequence represented by this object, or -1 if the character does not occur. |
indexOf
fun indexOf(
ch: Int,
fromIndex: Int
): Int
Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.
If a character with value ch
occurs in the character sequence represented by this String
object at an index no smaller than fromIndex
, then the index of the first such occurrence is returned. For values of ch
in the range from 0 to 0xFFFF (inclusive), this is the smallest value k such that:
(this.charAt(<i>k</i>) == ch) <code>&&</code>(<i>k</i>>= fromIndex)
ch
, it is the smallest value k such that:
(this.codePointAt(<i>k</i>) == ch) <code>&&</code>(<i>k</i>>= fromIndex)
fromIndex
, then -1
is returned.
There is no restriction on the value of fromIndex
. If it is negative, it has the same effect as if it were zero: this entire string may be searched. If it is greater than the length of this string, it has the same effect as if it were equal to the length of this string: -1
is returned.
All indices are specified in char
values (Unicode code units).
Parameters | |
---|---|
ch |
Int: a character (Unicode code point). |
fromIndex |
Int: the index to start the search from. |
Return | |
---|---|
Int |
the index of the first occurrence of the character in the character sequence represented by this object that is greater than or equal to fromIndex , or -1 if the character does not occur. |
indexOf
fun indexOf(str: String): Int
Returns the index within this string of the first occurrence of the specified substring.
The returned index is the smallest value k
for which:
<code>this.startsWith(str, k) </code>
k
exists, then -1
is returned.
Parameters | |
---|---|
str |
String: the substring to search for. |
Return | |
---|---|
Int |
the index of the first occurrence of the specified substring, or -1 if there is no such occurrence. |
indexOf
fun indexOf(
str: String,
fromIndex: Int
): Int
Returns the index within this string of the first occurrence of the specified substring, starting at the specified index.
The returned index is the smallest value k
for which:
<code>k >= Math.min(fromIndex, this.length()) && this.startsWith(str, k) </code>
k
exists, then -1
is returned.
Parameters | |
---|---|
str |
String: the substring to search for. |
fromIndex |
Int: the index from which to start the search. |
Return | |
---|---|
Int |
the index of the first occurrence of the specified substring, starting at the specified index, or -1 if there is no such occurrence. |
intern
fun intern(): String
Returns a canonical representation for the string object.
A pool of strings, initially empty, is maintained privately by the class String
.
When the intern method is invoked, if the pool already contains a string equal to this String
object as determined by the equals(java.lang.Object)
method, then the string from the pool is returned. Otherwise, this String
object is added to the pool and a reference to this String
object is returned.
It follows that for any two strings s
and t
, s.intern() == t.intern()
is true
if and only if s.equals(t)
is true
.
All literal strings and string-valued constant expressions are interned. String literals are defined in section 3.10.5 of the The Java™ Language Specification.
Return | |
---|---|
String |
a string that has the same contents as this string, but is guaranteed to be from a pool of unique strings. |
isBlank
fun isBlank(): Boolean
Returns true
if the string is empty or contains only white space
codepoints, otherwise false
.
Return | |
---|---|
Boolean |
true if the string is empty or contains only white space codepoints, otherwise false |
isEmpty
fun isEmpty(): Boolean
Returns true
if, and only if, length()
is 0
.
Return | |
---|---|
Boolean |
true if length() is 0 , otherwise false |
join
static fun join(
delimiter: CharSequence,
vararg elements: CharSequence!
): String
Returns a new String composed of copies of the CharSequence elements
joined together with a copy of the specified delimiter
. For example,
<code>String message = String.join("-", "Java", "is", "cool"); // message returned is: "Java-is-cool" </code>
"null"
is added.
Parameters | |
---|---|
delimiter |
CharSequence: the delimiter that separates each element |
elements |
CharSequence!: the elements to join together. |
Return | |
---|---|
String |
a new String that is composed of the elements separated by the delimiter |
Exceptions | |
---|---|
java.lang.NullPointerException |
If delimiter or elements is null |
See Also
join
static fun join(
delimiter: CharSequence,
elements: MutableIterable<CharSequence!>
): String
Returns a new String
composed of copies of the CharSequence elements
joined together with a copy of the specified delimiter
. For example,
<code>List<String> strings = List.of("Java", "is", "cool"); String message = String.join(" ", strings); //message returned is: "Java is cool" Set<String> strings = new LinkedHashSet<>(List.of("Java", "is", "very", "cool")); String message = String.join("-", strings); //message returned is: "Java-is-very-cool" </code>
null
, then "null"
is added.
Parameters | |
---|---|
delimiter |
CharSequence: a sequence of characters that is used to separate each of the elements in the resulting String |
elements |
MutableIterable<CharSequence!>: an Iterable that will have its elements joined together. |
Return | |
---|---|
String |
a new String that is composed from the elements argument |
Exceptions | |
---|---|
java.lang.NullPointerException |
If delimiter or elements is null |
lastIndexOf
fun lastIndexOf(ch: Int): Int
Returns the index within this string of the last occurrence of the specified character. For values of ch
in the range from 0 to 0xFFFF (inclusive), the index (in Unicode code units) returned is the largest value k such that:
this.charAt(<i>k</i>) == ch
ch
, it is the largest value k such that:
this.codePointAt(<i>k</i>) == ch
-1
is returned. The String
is searched backwards starting at the last character.
Parameters | |
---|---|
ch |
Int: a character (Unicode code point). |
Return | |
---|---|
Int |
the index of the last occurrence of the character in the character sequence represented by this object, or -1 if the character does not occur. |
lastIndexOf
fun lastIndexOf(
ch: Int,
fromIndex: Int
): Int
Returns the index within this string of the last occurrence of the specified character, searching backward starting at the specified index. For values of ch
in the range from 0 to 0xFFFF (inclusive), the index returned is the largest value k such that:
(this.charAt(<i>k</i>) == ch) <code>&&</code>(<i>k</i><= fromIndex)
ch
, it is the largest value k such that:
(this.codePointAt(<i>k</i>) == ch) <code>&&</code>(<i>k</i><= fromIndex)
fromIndex
, then -1
is returned.
All indices are specified in char
values (Unicode code units).
Parameters | |
---|---|
ch |
Int: a character (Unicode code point). |
fromIndex |
Int: the index to start the search from. There is no restriction on the value of fromIndex . If it is greater than or equal to the length of this string, it has the same effect as if it were equal to one less than the length of this string: this entire string may be searched. If it is negative, it has the same effect as if it were -1: -1 is returned. |
Return | |
---|---|
Int |
the index of the last occurrence of the character in the character sequence represented by this object that is less than or equal to fromIndex , or -1 if the character does not occur before that point. |
lastIndexOf
fun lastIndexOf(str: String): Int
Returns the index within this string of the last occurrence of the specified substring. The last occurrence of the empty string "" is considered to occur at the index value this.length()
.
The returned index is the largest value k
for which:
<code>this.startsWith(str, k) </code>
k
exists, then -1
is returned.
Parameters | |
---|---|
str |
String: the substring to search for. |
Return | |
---|---|
Int |
the index of the last occurrence of the specified substring, or -1 if there is no such occurrence. |
lastIndexOf
fun lastIndexOf(
str: String,
fromIndex: Int
): Int
Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.
The returned index is the largest value k
for which:
<code>k <= Math.min(fromIndex, this.length()) && this.startsWith(str, k) </code>
k
exists, then -1
is returned.
Parameters | |
---|---|
str |
String: the substring to search for. |
fromIndex |
Int: the index to start the search from. |
Return | |
---|---|
Int |
the index of the last occurrence of the specified substring, searching backward from the specified index, or -1 if there is no such occurrence. |
lines
fun lines(): Stream<String!>
Returns a stream of lines extracted from this string, separated by line terminators.
A line terminator is one of the following: a line feed character "\n"
(U+000A), a carriage return character "\r"
(U+000D), or a carriage return followed immediately by a line feed "\r\n"
(U+000D U+000A).
A line is either a sequence of zero or more characters followed by a line terminator, or it is a sequence of one or more characters followed by the end of the string. A line does not include the line terminator.
The stream returned by this method contains the lines from this string in the order in which they occur.
Return | |
---|---|
Stream<String!> |
the stream of lines extracted from this string |
matches
fun matches(regex: String): Boolean
Tells whether or not this string matches the given regular expression.
An invocation of this method of the form str.matches(
regex)
yields exactly the same result as the expression
java.util.regex.Pattern
. matches(regex, str)
Parameters | |
---|---|
regex |
String: the regular expression to which this string is to be matched |
Return | |
---|---|
Boolean |
true if, and only if, this string matches the given regular expression |
Exceptions | |
---|---|
java.util.regex.PatternSyntaxException |
if the regular expression's syntax is invalid |
See Also
offsetByCodePoints
fun offsetByCodePoints(
index: Int,
codePointOffset: Int
): Int
Returns the index within this String
that is offset from the given index
by codePointOffset
code points. Unpaired surrogates within the text range given by index
and codePointOffset
count as one code point each.
Parameters | |
---|---|
index |
Int: the index to be offset |
codePointOffset |
Int: the offset in code points |
Return | |
---|---|
Int |
the index within this String |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if index is negative or larger then the length of this String , or if codePointOffset is positive and the substring starting with index has fewer than codePointOffset code points, or if codePointOffset is negative and the substring before index has fewer than the absolute value of codePointOffset code points. |
regionMatches
fun regionMatches(
toffset: Int,
other: String,
ooffset: Int,
len: Int
): Boolean
Tests if two string regions are equal.
A substring of this String
object is compared to a substring of the argument other. The result is true if these substrings represent identical character sequences. The substring of this String
object to be compared begins at index toffset
and has length len
. The substring of other to be compared begins at index ooffset
and has length len
. The result is false
if and only if at least one of the following is true:
toffset
is negative.ooffset
is negative.toffset+len
is greater than the length of thisString
object.ooffset+len
is greater than the length of the other argument.- There is some nonnegative integer k less than
len
such that:this.charAt(toffset +
k) != other.charAt(ooffset +
k)
Note that this method does not take locale into account. The java.text.Collator
class provides locale-sensitive comparison.
Parameters | |
---|---|
toffset |
Int: the starting offset of the subregion in this string. |
other |
String: the string argument. |
ooffset |
Int: the starting offset of the subregion in the string argument. |
len |
Int: the number of characters to compare. |
Return | |
---|---|
Boolean |
true if the specified subregion of this string exactly matches the specified subregion of the string argument; false otherwise. |
regionMatches
fun regionMatches(
ignoreCase: Boolean,
toffset: Int,
other: String,
ooffset: Int,
len: Int
): Boolean
Tests if two string regions are equal.
A substring of this String
object is compared to a substring of the argument other
. The result is true
if these substrings represent character sequences that are the same, ignoring case if and only if ignoreCase
is true. The substring of this String
object to be compared begins at index toffset
and has length len
. The substring of other
to be compared begins at index ooffset
and has length len
. The result is false
if and only if at least one of the following is true:
toffset
is negative.ooffset
is negative.toffset+len
is greater than the length of thisString
object.ooffset+len
is greater than the length of the other argument.ignoreCase
isfalse
and there is some nonnegative integer k less thanlen
such that:this.charAt(toffset+k) != other.charAt(ooffset+k)
ignoreCase
istrue
and there is some nonnegative integer k less thanlen
such that:Character.toLowerCase(Character.toUpperCase(this.charAt(toffset+k))) != Character.toLowerCase(Character.toUpperCase(other.charAt(ooffset+k)))
Note that this method does not take locale into account, and will result in unsatisfactory results for certain locales when ignoreCase
is true
. The java.text.Collator
class provides locale-sensitive comparison.
Parameters | |
---|---|
ignoreCase |
Boolean: if true , ignore case when comparing characters. |
toffset |
Int: the starting offset of the subregion in this string. |
other |
String: the string argument. |
ooffset |
Int: the starting offset of the subregion in the string argument. |
len |
Int: the number of characters to compare. |
Return | |
---|---|
Boolean |
true if the specified subregion of this string matches the specified subregion of the string argument; false otherwise. Whether the matching is exact or case insensitive depends on the ignoreCase argument. |
repeat
fun repeat(count: Int): String
Returns a string whose value is the concatenation of this string repeated count
times.
If this string is empty or count is zero then the empty string is returned.
Parameters | |
---|---|
count |
Int: number of times to repeat |
Return | |
---|---|
String |
A string composed of this string repeated count times or the empty string if this string is empty or count is zero |
Exceptions | |
---|---|
java.lang.IllegalArgumentException |
if the count is negative. |
replace
fun replace(
oldChar: Char,
newChar: Char
): String
Returns a string resulting from replacing all occurrences of oldChar
in this string with newChar
.
If the character oldChar
does not occur in the character sequence represented by this String
object, then a reference to this String
object is returned. Otherwise, a String
object is returned that represents a character sequence identical to the character sequence represented by this String
object, except that every occurrence of oldChar
is replaced by an occurrence of newChar
.
Examples:
"mesquite in your cellar".replace('e', 'o') returns "mosquito in your collar" "the war of baronets".replace('r', 'y') returns "the way of bayonets" "sparring with a purple porpoise".replace('p', 't') returns "starring with a turtle tortoise" "JonL".replace('q', 'x') returns "JonL" (no change)
Parameters | |
---|---|
oldChar |
Char: the old character. |
newChar |
Char: the new character. |
Return | |
---|---|
String |
a string derived from this string by replacing every occurrence of oldChar with newChar . |
replace
fun replace(
target: CharSequence,
replacement: CharSequence
): String
Replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence. The replacement proceeds from the beginning of the string to the end, for example, replacing "aa" with "b" in the string "aaa" will result in "ba" rather than "ab".
Parameters | |
---|---|
target |
CharSequence: The sequence of char values to be replaced |
replacement |
CharSequence: The replacement sequence of char values |
Return | |
---|---|
String |
The resulting string |
replaceAll
fun replaceAll(
regex: String,
replacement: String
): String
Replaces each substring of this string that matches the given regular expression with the given replacement.
An invocation of this method of the form str.replaceAll(
regex,
repl)
yields exactly the same result as the expression
java.util.regex.Pattern
.java.util.regex.Pattern#compile(regex).matcher
(str).java.util.regex.Matcher#replaceAll(repl)
Note that backslashes (\
) and dollar signs ($
) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; see java.util.regex.Matcher#replaceAll. Use java.util.regex.Matcher#quoteReplacement
to suppress the special meaning of these characters, if desired.
Parameters | |
---|---|
regex |
String: the regular expression to which this string is to be matched |
replacement |
String: the string to be substituted for each match |
Return | |
---|---|
String |
The resulting String |
Exceptions | |
---|---|
java.util.regex.PatternSyntaxException |
if the regular expression's syntax is invalid |
See Also
replaceFirst
fun replaceFirst(
regex: String,
replacement: String
): String
Replaces the first substring of this string that matches the given regular expression with the given replacement.
An invocation of this method of the form str.replaceFirst(
regex,
repl)
yields exactly the same result as the expression
java.util.regex.Pattern
.java.util.regex.Pattern#compile(regex).matcher
(str).java.util.regex.Matcher#replaceFirst(repl)
Note that backslashes (\
) and dollar signs ($
) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; see java.util.regex.Matcher#replaceFirst. Use java.util.regex.Matcher#quoteReplacement
to suppress the special meaning of these characters, if desired.
Parameters | |
---|---|
regex |
String: the regular expression to which this string is to be matched |
replacement |
String: the string to be substituted for the first match |
Return | |
---|---|
String |
The resulting String |
Exceptions | |
---|---|
java.util.regex.PatternSyntaxException |
if the regular expression's syntax is invalid |
See Also
split
fun split(
regex: String,
limit: Int
): Array<String!>
Splits this string around matches of the given regular expression.
The array returned by this method contains each substring of this string that is terminated by another substring that matches the given expression or is terminated by the end of the string. The substrings in the array are in the order in which they occur in this string. If the expression does not match any part of the input then the resulting array has just one element, namely this string.
When there is a positive-width match at the beginning of this string then an empty leading substring is included at the beginning of the resulting array. A zero-width match at the beginning however never produces such empty leading substring.
The limit
parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array.
- If the limit is positive then the pattern will be applied at most limit - 1 times, the array's length will be no greater than limit, and the array's last entry will contain all input beyond the last matched delimiter.
- If the limit is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.
- If the limit is negative then the pattern will be applied as many times as possible and the array can have any length.
The string "boo:and:foo"
, for example, yields the following results with these parameters:
Regex | Limit | Result |
---|---|---|
: | 2 | { "boo", "and:foo" } |
5 | { "boo", "and", "foo" } |
|
-2 | { "boo", "and", "foo" } |
|
o | 5 | { "b", "", ":and:f", "", "" } |
-2 | { "b", "", ":and:f", "", "" } |
|
0 | { "b", "", ":and:f" } |
An invocation of this method of the form str.split(
regex,
n)
yields the same result as the expression
java.util.regex.Pattern
.java.util.regex.Pattern#compile(regex).split
(str, n)
Parameters | |
---|---|
regex |
String: the delimiting regular expression |
limit |
Int: the result threshold, as described above |
Return | |
---|---|
Array<String!> |
the array of strings computed by splitting this string around matches of the given regular expression |
Exceptions | |
---|---|
java.util.regex.PatternSyntaxException |
if the regular expression's syntax is invalid |
See Also
split
fun split(regex: String): Array<String!>
Splits this string around matches of the given regular expression.
This method works as if by invoking the two-argument split
method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.
The string "boo:and:foo"
, for example, yields the following results with these expressions:
Regex | Result |
---|---|
: | { "boo", "and", "foo" } |
o | { "b", "", ":and:f" } |
Parameters | |
---|---|
regex |
String: the delimiting regular expression |
Return | |
---|---|
Array<String!> |
the array of strings computed by splitting this string around matches of the given regular expression |
Exceptions | |
---|---|
java.util.regex.PatternSyntaxException |
if the regular expression's syntax is invalid |
See Also
startsWith
fun startsWith(
prefix: String,
toffset: Int
): Boolean
Tests if the substring of this string beginning at the specified index starts with the specified prefix.
Parameters | |
---|---|
prefix |
String: the prefix. |
toffset |
Int: where to begin looking in this string. |
Return | |
---|---|
Boolean |
true if the character sequence represented by the argument is a prefix of the substring of this object starting at index toffset ; false otherwise. The result is false if toffset is negative or greater than the length of this String object; otherwise the result is the same as the result of the expression
this.substring(toffset).startsWith(prefix) |
startsWith
fun startsWith(prefix: String): Boolean
Tests if this string starts with the specified prefix.
Parameters | |
---|---|
prefix |
String: the prefix. |
Return | |
---|---|
Boolean |
true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; false otherwise. Note also that true will be returned if the argument is an empty string or is equal to this String object as determined by the equals(java.lang.Object) method. |
strip
fun strip(): String
Returns a string whose value is this string, with all leading and trailing white space
removed.
If this String
object represents an empty string, or if all code points in this string are white space
, then an empty string is returned.
Otherwise, returns a substring of this string beginning with the first code point that is not a white space
up to and including the last code point that is not a white space
.
This method may be used to strip white space
from the beginning and end of a string.
Return | |
---|---|
String |
a string whose value is this string, with all leading and trailing white space removed |
stripIndent
fun stripIndent(): String
Returns a string whose value is this string, with incidental removed from the beginning and end of every line.
Incidental white space is often present in a text block to align the content with the opening delimiter. For example, in the following code, dots represent incidental white space:
String html = """ ..............<html> .............. <body> .............. <p>Hello, world</p> .............. </body> ..............</html> ..............""";
|<html> | <body> | <p>Hello, world</p> | </body> |</html>
Then, the minimum indentation (min) is determined as follows:
-
For each non-blank line (as defined by
String#isBlank()
), the leading white space characters are counted. -
The leading white space characters on the last line are also counted even if blank.
The min value is the smallest of these counts.
For each non-blank line, min leading white space characters are removed, and any trailing space characters are removed. Blank lines are replaced with the empty string.
Finally, the lines are joined into a new string, using the LF character "\n"
(U+000A) to separate lines.
Return | |
---|---|
String |
string with incidental indentation removed and line terminators normalized |
stripLeading
fun stripLeading(): String
Returns a string whose value is this string, with all leading white space
removed.
If this String
object represents an empty string, or if all code points in this string are white space
, then an empty string is returned.
Otherwise, returns a substring of this string beginning with the first code point that is not a white space
up to to and including the last code point of this string.
This method may be used to trim white space
from the beginning of a string.
Return | |
---|---|
String |
a string whose value is this string, with all leading white space removed |
stripTrailing
fun stripTrailing(): String
Returns a string whose value is this string, with all trailing white space
removed.
If this String
object represents an empty string, or if all characters in this string are white space
, then an empty string is returned.
Otherwise, returns a substring of this string beginning with the first code point of this string up to and including the last code point that is not a white space
.
This method may be used to trim white space
from the end of a string.
Return | |
---|---|
String |
a string whose value is this string, with all trailing white space removed |
subSequence
fun subSequence(
startIndex: Int,
endIndex: Int
): CharSequence
Returns a character sequence that is a subsequence of this sequence.
An invocation of this method of the form
str.subSequence(begin, end)
str.substring(begin, end)
Parameters | |
---|---|
start |
the start index, inclusive |
end |
the end index, exclusive |
beginIndex |
the begin index, inclusive. |
endIndex |
Int: the end index, exclusive. |
Return | |
---|---|
CharSequence |
the specified subsequence. |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if beginIndex or endIndex is negative, if endIndex is greater than length() , or if beginIndex is greater than endIndex |
substring
fun substring(beginIndex: Int): String
Returns a string that is a substring of this string. The substring begins with the character at the specified index and extends to the end of this string.
Examples:
"unhappy".substring(2) returns "happy" "Harbison".substring(3) returns "bison" "emptiness".substring(9) returns "" (an empty string)
Parameters | |
---|---|
beginIndex |
Int: the beginning index, inclusive. |
Return | |
---|---|
String |
the specified substring. |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if beginIndex is negative or larger than the length of this String object. |
substring
fun substring(
beginIndex: Int,
endIndex: Int
): String
Returns a string that is a substring of this string. The substring begins at the specified beginIndex
and extends to the character at index endIndex - 1
. Thus the length of the substring is endIndex-beginIndex
.
Examples:
"hamburger".substring(4, 8) returns "urge" "smiles".substring(1, 5) returns "mile"
Parameters | |
---|---|
beginIndex |
Int: the beginning index, inclusive. |
endIndex |
Int: the ending index, exclusive. |
Return | |
---|---|
String |
the specified substring. |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if the beginIndex is negative, or endIndex is larger than the length of this String object, or beginIndex is larger than endIndex . |
toCharArray
fun toCharArray(): CharArray!
Converts this string to a new character array.
Return | |
---|---|
CharArray! |
a newly allocated character array whose length is the length of this string and whose contents are initialized to contain the character sequence represented by this string. |
toLowerCase
fun toLowerCase(locale: Locale): String
Converts all of the characters in this String
to lower case using the rules of the given Locale
. Case mapping is based on the Unicode Standard version specified by the Character
class. Since case mappings are not always 1:1 char mappings, the resulting String
may be a different length than the original String
.
Examples of lowercase mappings are in the following table:
Language Code of Locale | Upper Case | Lower Case | Description |
---|---|---|---|
tr (Turkish) | \u0130 | \u0069 | capital letter I with dot above -> small letter i |
tr (Turkish) | \u0049 | \u0131 | capital letter I -> small letter dotless i |
(all) | French Fries | french fries | lowercased all chars in String |
(all) | ΙΧΘΥΣ | ιχθυσ | lowercased all chars in String |
Parameters | |
---|---|
locale |
Locale: use the case transformation rules for this locale |
Return | |
---|---|
String |
the String , converted to lowercase. |
toLowerCase
fun toLowerCase(): String
Converts all of the characters in this String
to lower case using the rules of the default locale. This is equivalent to calling toLowerCase(Locale.getDefault())
.
Note: This method is locale sensitive, and may produce unexpected results if used for strings that are intended to be interpreted locale independently. Examples are programming language identifiers, protocol keys, and HTML tags. For instance, "TITLE".toLowerCase()
in a Turkish locale returns "t\u005Cu0131tle"
, where '\u005Cu0131' is the LATIN SMALL LETTER DOTLESS I character. To obtain correct results for locale insensitive strings, use toLowerCase(Locale.ROOT)
.
Return | |
---|---|
String |
the String , converted to lowercase. |
See Also
toString
fun toString(): String
This object (which is already a string!) is itself returned.
Return | |
---|---|
String |
the string itself. |
toUpperCase
fun toUpperCase(locale: Locale): String
Converts all of the characters in this String
to upper case using the rules of the given Locale
. Case mapping is based on the Unicode Standard version specified by the Character
class. Since case mappings are not always 1:1 char mappings, the resulting String
may be a different length than the original String
.
Examples of locale-sensitive and 1:M case mappings are in the following table.
Language Code of Locale | Lower Case | Upper Case | Description |
---|---|---|---|
tr (Turkish) | \u0069 | \u0130 | small letter i -> capital letter I with dot above |
tr (Turkish) | \u0131 | \u0049 | small letter dotless i -> capital letter I |
(all) | \u00df | \u0053 \u0053 | small letter sharp s -> two letters: SS |
(all) | Fahrvergnügen | FAHRVERGNÜGEN |
Parameters | |
---|---|
locale |
Locale: use the case transformation rules for this locale |
Return | |
---|---|
String |
the String , converted to uppercase. |
toUpperCase
fun toUpperCase(): String
Converts all of the characters in this String
to upper case using the rules of the default locale. This method is equivalent to toUpperCase(Locale.getDefault())
.
Note: This method is locale sensitive, and may produce unexpected results if used for strings that are intended to be interpreted locale independently. Examples are programming language identifiers, protocol keys, and HTML tags. For instance, "title".toUpperCase()
in a Turkish locale returns "T\u005Cu0130TLE"
, where '\u005Cu0130' is the LATIN CAPITAL LETTER I WITH DOT ABOVE character. To obtain correct results for locale insensitive strings, use toUpperCase(Locale.ROOT)
.
Return | |
---|---|
String |
the String , converted to uppercase. |
See Also
transform
fun <R : Any!> transform(f: Function<in String!, out R>): R
This method allows the application of a function to this
string. The function should expect a single String argument and produce an R
result.
Any exception thrown by f.apply()
will be propagated to the caller.
Parameters | |
---|---|
f |
Function<in String!, out R>: a function to apply |
<R> |
the type of the result |
Return | |
---|---|
R |
the result of applying the function to this string |
See Also
translateEscapes
fun translateEscapes(): String
Returns a string whose value is this string, with escape sequences translated as if in a string literal.
Escape sequences are translated as follows;
Escape | Name | Translation |
---|---|---|
\u005Cb |
backspace | U+0008 |
\u005Ct |
horizontal tab | U+0009 |
\u005Cn |
line feed | U+000A |
\u005Cf |
form feed | U+000C |
\u005Cr |
carriage return | U+000D |
\u005Cs |
space | U+0020 |
\u005C" |
double quote | U+0022 |
\u005C' |
single quote | U+0027 |
\u005C\u005C |
backslash | U+005C |
\u005C0 - \u005C377 |
octal escape | code point equivalents |
\u005C<line-terminator> |
continuation | discard |
Return | |
---|---|
String |
String with escape sequences translated. |
Exceptions | |
---|---|
java.lang.IllegalArgumentException |
when an escape sequence is malformed. |
trim
fun trim(): String
Returns a string whose value is this string, with all leading and trailing space removed, where space is defined as any character whose codepoint is less than or equal to 'U+0020'
(the space character).
If this String
object represents an empty character sequence, or the first and last characters of character sequence represented by this String
object both have codes that are not space (as defined above), then a reference to this String
object is returned.
Otherwise, if all characters in this string are space (as defined above), then a String
object representing an empty string is returned.
Otherwise, let k be the index of the first character in the string whose code is not a space (as defined above) and let m be the index of the last character in the string whose code is not a space (as defined above). A String
object is returned, representing the substring of this string that begins with the character at index k and ends with the character at index m-that is, the result of this.substring(k, m + 1)
.
This method may be used to trim space (as defined above) from the beginning and end of a string.
Return | |
---|---|
String |
a string whose value is this string, with all leading and trailing space removed, or this string if it has no leading or trailing space. |
valueOf
static fun valueOf(obj: Any?): String
Returns the string representation of the Object
argument.
Parameters | |
---|---|
obj |
Any?: an Object . |
Return | |
---|---|
String |
if the argument is null , then a string equal to "null" ; otherwise, the value of obj.toString() is returned. |
See Also
valueOf
static fun valueOf(data: CharArray!): String
Returns the string representation of the char
array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the returned string.
Parameters | |
---|---|
data |
CharArray!: the character array. |
Return | |
---|---|
String |
a String that contains the characters of the character array. |
valueOf
static fun valueOf(
data: CharArray!,
offset: Int,
count: Int
): String
Returns the string representation of a specific subarray of the char
array argument.
The offset
argument is the index of the first character of the subarray. The count
argument specifies the length of the subarray. The contents of the subarray are copied; subsequent modification of the character array does not affect the returned string.
Parameters | |
---|---|
data |
CharArray!: the character array. |
offset |
Int: initial offset of the subarray. |
count |
Int: length of the subarray. |
Return | |
---|---|
String |
a String that contains the characters of the specified subarray of the character array. |
Exceptions | |
---|---|
java.lang.IndexOutOfBoundsException |
if offset is negative, or count is negative, or offset+count is larger than data.length . |
valueOf
static fun valueOf(b: Boolean): String
Returns the string representation of the boolean
argument.
Parameters | |
---|---|
b |
Boolean: a boolean . |
Return | |
---|---|
String |
if the argument is true , a string equal to "true" is returned; otherwise, a string equal to "false" is returned. |
valueOf
static fun valueOf(c: Char): String
Returns the string representation of the char
argument.
Parameters | |
---|---|
c |
Char: a char . |
Return | |
---|---|
String |
a string of length 1 containing as its single character the argument c . |
valueOf
static fun valueOf(i: Int): String
Returns the string representation of the int
argument.
The representation is exactly the one returned by the Integer.toString
method of one argument.
Parameters | |
---|---|
i |
Int: an int . |
Return | |
---|---|
String |
a string representation of the int argument. |
See Also
valueOf
static fun valueOf(l: Long): String
Returns the string representation of the long
argument.
The representation is exactly the one returned by the Long.toString
method of one argument.
Parameters | |
---|---|
l |
Long: a long . |
Return | |
---|---|
String |
a string representation of the long argument. |
See Also
valueOf
static fun valueOf(f: Float): String
Returns the string representation of the float
argument.
The representation is exactly the one returned by the Float.toString
method of one argument.
Parameters | |
---|---|
f |
Float: a float . |
Return | |
---|---|
String |
a string representation of the float argument. |
See Also
valueOf
static fun valueOf(d: Double): String
Returns the string representation of the double
argument.
The representation is exactly the one returned by the Double.toString
method of one argument.
Parameters | |
---|---|
d |
Double: a double . |
Return | |
---|---|
String |
a string representation of the double argument. |
See Also
Properties
CASE_INSENSITIVE_ORDER
static val CASE_INSENSITIVE_ORDER: Comparator<String!>!
A Comparator that orders String
objects as by compareToIgnoreCase
. This comparator is serializable.
Note that this Comparator does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The java.text.Collator
class provides locale-sensitive comparison.
See Also
length
val length: Int
Returns the length of this string. The length is equal to the number of Unicode code units in the string.
Return | |
---|---|
Int |
the length of the sequence of characters represented by this object. |