Documentation
¶
Overview ¶
Package strings implements simple functions to manipulate UTF-8 encoded strings.
For information about UTF-8 strings in Go, see https://blog.golang.org/strings.
Index ¶
- func Clone(s string) string
- func Compare(a string, b string) int
- func Contains(s string, substr string) bool
- func ContainsAny(s string, chars string) bool
- func ContainsFunc(s string, f func(rune) bool) bool
- func ContainsRune(s string, r rune) bool
- func Count(s string, substr string) int
- func Cut(s string, sep string) (before string, after string, found bool)
- func CutPrefix(s string, prefix string) (after string, found bool)
- func CutSuffix(s string, suffix string) (before string, found bool)
- func EqualFold(s string, t string) bool
- func Fields(s string) []string
- func FieldsFunc(s string, f func(rune) bool) []string
- func FieldsFuncSeq(s string, f func(rune) bool) iter.Seq[string]
- func FieldsSeq(s string) iter.Seq[string]
- func HasPrefix(s string, prefix string) bool
- func HasSuffix(s string, suffix string) bool
- func Index(s string, substr string) int
- func IndexAny(s string, chars string) int
- func IndexByte(s string, c byte) int
- func IndexFunc(s string, f func(rune) bool) int
- func IndexRune(s string, r rune) int
- func Join(elems []string, sep string) string
- func LastIndex(s string, substr string) int
- func LastIndexAny(s string, chars string) int
- func LastIndexByte(s string, c byte) int
- func LastIndexFunc(s string, f func(rune) bool) int
- func Lines(s string) iter.Seq[string]
- func Map(mapping func(rune) rune, s string) string
- func NewReader(s string) *strings.Reader
- func NewReplacer(oldnew ...string) *strings.Replacer
- func Random(n int, charset []rune) string
- func Repeat(s string, count int) string
- func Replace(s string, old string, new string, n int) string
- func ReplaceAll(s string, old string, new string) string
- func Split(s string, sep string) []string
- func SplitAfter(s string, sep string) []string
- func SplitAfterN(s string, sep string, n int) []string
- func SplitAfterSeq(s string, sep string) iter.Seq[string]
- func SplitN(s string, sep string, n int) []string
- func SplitSeq(s string, sep string) iter.Seq[string]
- func Title(s string) stringdeprecated
- func ToLower(s string) string
- func ToLowerSpecial(c unicode.SpecialCase, s string) string
- func ToTitle(s string) string
- func ToTitleSpecial(c unicode.SpecialCase, s string) string
- func ToUpper(s string) string
- func ToUpperSpecial(c unicode.SpecialCase, s string) string
- func ToValidUTF8(s string, replacement string) string
- func Trim(s string, cutset string) string
- func TrimFunc(s string, f func(rune) bool) string
- func TrimLeft(s string, cutset string) string
- func TrimLeftFunc(s string, f func(rune) bool) string
- func TrimPrefix(s string, prefix string) string
- func TrimRight(s string, cutset string) string
- func TrimRightFunc(s string, f func(rune) bool) string
- func TrimSpace(s string) string
- func TrimSuffix(s string, suffix string) string
- func WriteJoining(sb *strings.Builder, elems []string, sep string)
- func WriteJoiningSeq(sb *strings.Builder, elems iter.Seq[string], sep string)
- type Builder
- type Reader
- type Replacer
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Clone ¶
Clone returns a fresh copy of s. It guarantees to make a copy of s into a new allocation, which can be important when retaining only a small substring of a much larger string. Using Clone can help such programs use less memory. Of course, since using Clone makes a copy, overuse of Clone can make programs use more memory. Clone should typically be used only rarely, and only when profiling indicates that it is needed. For strings of length zero the string "" will be returned and no allocation is made.
func Compare ¶
Compare returns an integer comparing two strings lexicographically. The result will be 0 if a == b, -1 if a < b, and +1 if a > b.
Use Compare when you need to perform a three-way comparison (with slices.SortFunc, for example). It is usually clearer and always faster to use the built-in string comparison operators ==, <, >, and so on.
func ContainsAny ¶
ContainsAny reports whether any Unicode code points in chars are within s.
func ContainsFunc ¶
ContainsFunc reports whether any Unicode code points r within s satisfy f(r).
func ContainsRune ¶
ContainsRune reports whether the Unicode code point r is within s.
func Count ¶
Count counts the number of non-overlapping instances of substr in s. If substr is an empty string, Count returns 1 + the number of Unicode code points in s.
func Cut ¶
Cut slices s around the first instance of sep, returning the text before and after sep. The found result reports whether sep appears in s. If sep does not appear in s, cut returns s, "", false.
func CutPrefix ¶
CutPrefix returns s without the provided leading prefix string and reports whether it found the prefix. If s doesn't start with prefix, CutPrefix returns s, false. If prefix is the empty string, CutPrefix returns s, true.
func CutSuffix ¶
CutSuffix returns s without the provided ending suffix string and reports whether it found the suffix. If s doesn't end with suffix, CutSuffix returns s, false. If suffix is the empty string, CutSuffix returns s, true.
func EqualFold ¶
EqualFold reports whether s and t, interpreted as UTF-8 strings, are equal under simple Unicode case-folding, which is a more general form of case-insensitivity.
func Fields ¶
Fields splits the string s around each instance of one or more consecutive white space characters, as defined by unicode.IsSpace, returning a slice of substrings of s or an empty slice if s contains only white space.
func FieldsFunc ¶
FieldsFunc splits the string s at each run of Unicode code points c satisfying f(c) and returns an array of slices of s. If all code points in s satisfy f(c) or the string is empty, an empty slice is returned.
FieldsFunc makes no guarantees about the order in which it calls f(c) and assumes that f always returns the same value for a given c.
func FieldsFuncSeq ¶
FieldsFuncSeq returns an iterator over substrings of s split around runs of Unicode code points satisfying f(c). The iterator yields the same strings that would be returned by FieldsFunc(s), but without constructing the slice.
func FieldsSeq ¶
FieldsSeq returns an iterator over substrings of s split around runs of whitespace characters, as defined by unicode.IsSpace. The iterator yields the same strings that would be returned by Fields(s), but without constructing the slice.
func Index ¶
Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
func IndexAny ¶
IndexAny returns the index of the first instance of any Unicode code point from chars in s, or -1 if no Unicode code point from chars is present in s.
func IndexByte ¶
IndexByte returns the index of the first instance of c in s, or -1 if c is not present in s.
func IndexFunc ¶
IndexFunc returns the index into s of the first Unicode code point satisfying f(c), or -1 if none do.
func IndexRune ¶
IndexRune returns the index of the first instance of the Unicode code point r, or -1 if rune is not present in s. If r is [utf8.RuneError], it returns the first instance of any invalid UTF-8 byte sequence.
func Join ¶
Join concatenates the elements of its first argument to create a single string. The separator string sep is placed between elements in the resulting string.
func LastIndex ¶
LastIndex returns the index of the last instance of substr in s, or -1 if substr is not present in s.
func LastIndexAny ¶
LastIndexAny returns the index of the last instance of any Unicode code point from chars in s, or -1 if no Unicode code point from chars is present in s.
func LastIndexByte ¶
LastIndexByte returns the index of the last instance of c in s, or -1 if c is not present in s.
func LastIndexFunc ¶
LastIndexFunc returns the index into s of the last Unicode code point satisfying f(c), or -1 if none do.
func Lines ¶
Lines returns an iterator over the newline-terminated lines in the string s. The lines yielded by the iterator include their terminating newlines. If s is empty, the iterator yields no lines at all. If s does not end in a newline, the final yielded line will not end in a newline. It returns a single-use iterator.
func Map ¶
Map returns a copy of the string s with all its characters modified according to the mapping function. If mapping returns a negative value, the character is dropped from the string with no replacement.
func NewReader ¶
NewReader returns a new Reader reading from s. It is similar to bytes.NewBufferString but more efficient and non-writable.
func NewReplacer ¶
NewReplacer returns a new Replacer from a list of old, new string pairs. Replacements are performed in the order they appear in the target string, without overlapping matches. The old string comparisons are done in argument order.
NewReplacer panics if given an odd number of arguments.
func Repeat ¶
Repeat returns a new string consisting of count copies of the string s.
It panics if count is negative or if the result of (len(s) * count) overflows.
func Replace ¶
Replace returns a copy of the string s with the first n non-overlapping instances of old replaced by new. If old is empty, it matches at the beginning of the string and after each UTF-8 sequence, yielding up to k+1 replacements for a k-rune string. If n < 0, there is no limit on the number of replacements.
func ReplaceAll ¶
ReplaceAll returns a copy of the string s with all non-overlapping instances of old replaced by new. If old is empty, it matches at the beginning of the string and after each UTF-8 sequence, yielding up to k+1 replacements for a k-rune string.
func Split ¶
Split slices s into all substrings separated by sep and returns a slice of the substrings between those separators.
If s does not contain sep and sep is not empty, Split returns a slice of length 1 whose only element is s.
If sep is empty, Split splits after each UTF-8 sequence. If both s and sep are empty, Split returns an empty slice.
It is equivalent to SplitN with a count of -1.
To split around the first instance of a separator, see Cut.
func SplitAfter ¶
SplitAfter slices s into all substrings after each instance of sep and returns a slice of those substrings.
If s does not contain sep and sep is not empty, SplitAfter returns a slice of length 1 whose only element is s.
If sep is empty, SplitAfter splits after each UTF-8 sequence. If both s and sep are empty, SplitAfter returns an empty slice.
It is equivalent to SplitAfterN with a count of -1.
func SplitAfterN ¶
SplitAfterN slices s into substrings after each instance of sep and returns a slice of those substrings.
The count determines the number of substrings to return:
- n > 0: at most n substrings; the last substring will be the unsplit remainder;
- n == 0: the result is nil (zero substrings);
- n < 0: all substrings.
Edge cases for s and sep (for example, empty strings) are handled as described in the documentation for SplitAfter.
func SplitAfterSeq ¶
SplitAfterSeq returns an iterator over substrings of s split after each instance of sep. The iterator yields the same strings that would be returned by SplitAfter(s, sep), but without constructing the slice. It returns a single-use iterator.
func SplitN ¶
SplitN slices s into substrings separated by sep and returns a slice of the substrings between those separators.
The count determines the number of substrings to return:
- n > 0: at most n substrings; the last substring will be the unsplit remainder;
- n == 0: the result is nil (zero substrings);
- n < 0: all substrings.
Edge cases for s and sep (for example, empty strings) are handled as described in the documentation for Split.
To split around the first instance of a separator, see Cut.
func SplitSeq ¶
SplitSeq returns an iterator over all substrings of s separated by sep. The iterator yields the same strings that would be returned by Split(s, sep), but without constructing the slice. It returns a single-use iterator.
func ToLowerSpecial ¶
func ToLowerSpecial(c unicode.SpecialCase, s string) string
ToLowerSpecial returns a copy of the string s with all Unicode letters mapped to their lower case using the case mapping specified by c.
func ToTitle ¶
ToTitle returns a copy of the string s with all Unicode letters mapped to their Unicode title case.
func ToTitleSpecial ¶
func ToTitleSpecial(c unicode.SpecialCase, s string) string
ToTitleSpecial returns a copy of the string s with all Unicode letters mapped to their Unicode title case, giving priority to the special casing rules.
func ToUpperSpecial ¶
func ToUpperSpecial(c unicode.SpecialCase, s string) string
ToUpperSpecial returns a copy of the string s with all Unicode letters mapped to their upper case using the case mapping specified by c.
func ToValidUTF8 ¶
ToValidUTF8 returns a copy of the string s with each run of invalid UTF-8 byte sequences replaced by the replacement string, which may be empty.
func Trim ¶
Trim returns a slice of the string s with all leading and trailing Unicode code points contained in cutset removed.
func TrimFunc ¶
TrimFunc returns a slice of the string s with all leading and trailing Unicode code points c satisfying f(c) removed.
func TrimLeft ¶
TrimLeft returns a slice of the string s with all leading Unicode code points contained in cutset removed.
To remove a prefix, use TrimPrefix instead.
func TrimLeftFunc ¶
TrimLeftFunc returns a slice of the string s with all leading Unicode code points c satisfying f(c) removed.
func TrimPrefix ¶
TrimPrefix returns s without the provided leading prefix string. If s doesn't start with prefix, s is returned unchanged.
func TrimRight ¶
TrimRight returns a slice of the string s, with all trailing Unicode code points contained in cutset removed.
To remove a suffix, use TrimSuffix instead.
func TrimRightFunc ¶
TrimRightFunc returns a slice of the string s with all trailing Unicode code points c satisfying f(c) removed.
func TrimSpace ¶
TrimSpace returns a slice of the string s, with all leading and trailing white space removed, as defined by Unicode.
func TrimSuffix ¶
TrimSuffix returns s without the provided trailing suffix string. If s doesn't end with suffix, s is returned unchanged.
func WriteJoining ¶
WriteJoining appends the elements of elems to the Builder, separated by sep.
Types ¶
type Builder ¶
A Builder is used to efficiently build a string using [Builder.Write] methods. It minimizes memory copying. The zero value is ready to use. Do not copy a non-zero Builder.
type Reader ¶
A Reader implements the io.Reader, io.ReaderAt, io.ByteReader, io.ByteScanner, io.RuneReader, io.RuneScanner, io.Seeker, and io.WriterTo interfaces by reading from a string. The zero value for Reader operates like a Reader of an empty string.
Source Files