W3cubDocs

Compare is included only for symmetry with package bytes. It is usually clearer and always faster to use the built-in string comparison operators ==, <, >, and so on.

func ContainsSource

func Contains(s, substr string) bool

Contains reports whether substr is within s.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Contains("seafood", "foo"))
	fmt.Println(strings.Contains("seafood", "bar"))
	fmt.Println(strings.Contains("seafood", ""))
	fmt.Println(strings.Contains("", ""))
}

func ContainsAnySource

func ContainsAny(s, chars string) bool

ContainsAny reports whether any Unicode code points in chars are within s.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.ContainsAny("team", "i"))
	fmt.Println(strings.ContainsAny("failure", "u & i"))
	fmt.Println(strings.ContainsAny("foo", ""))
	fmt.Println(strings.ContainsAny("", ""))
}

func ContainsRuneSource

func ContainsRune(s string, r rune) bool

ContainsRune reports whether the Unicode code point r is within s.

func CountSource

func Count(s, sep string) int

Count counts the number of non-overlapping instances of sep in s. If sep is an empty string, Count returns 1 + the number of Unicode code points in s.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Count("cheese", "e"))
	fmt.Println(strings.Count("five", "")) // before & after each rune
}

func EqualFoldSource

func EqualFold(s, t string) bool

EqualFold reports whether s and t, interpreted as UTF-8 strings, are equal under Unicode case-folding.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.EqualFold("Go", "go"))
}

func FieldsSource

func Fields(s string) []string

Fields splits the string s around each instance of one or more consecutive white space characters, as defined by unicode.IsSpace, returning an array of substrings of s or an empty list if s contains only white space.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Printf("Fields are: %q", strings.Fields("  foo bar  baz   "))
}

func FieldsFuncSource

func FieldsFunc(s string, f func(rune) bool) []string

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). If f does not return consistent results for a given c, FieldsFunc may crash.

Example

package main

import (
	"fmt"
	"strings"
	"unicode"
)

func main() {
	f := func(c rune) bool {
		return !unicode.IsLetter(c) && !unicode.IsNumber(c)
	}
	fmt.Printf("Fields are: %q", strings.FieldsFunc("  foo1;bar2,baz3...", f))
}

func HasPrefixSource

func HasPrefix(s, prefix string) bool

HasPrefix tests whether the string s begins with prefix.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.HasPrefix("Gopher", "Go"))
	fmt.Println(strings.HasPrefix("Gopher", "C"))
	fmt.Println(strings.HasPrefix("Gopher", ""))
}

func HasSuffixSource

func HasSuffix(s, suffix string) bool

HasSuffix tests whether the string s ends with suffix.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.HasSuffix("Amigo", "go"))
	fmt.Println(strings.HasSuffix("Amigo", "O"))
	fmt.Println(strings.HasSuffix("Amigo", "Ami"))
	fmt.Println(strings.HasSuffix("Amigo", ""))
}

func IndexSource

func Index(s, sep string) int

Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Index("chicken", "ken"))
	fmt.Println(strings.Index("chicken", "dmr"))
}

func IndexAnySource

func IndexAny(s, chars string) int

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.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.IndexAny("chicken", "aeiouy"))
	fmt.Println(strings.IndexAny("crwth", "aeiouy"))
}

func IndexByteSource

func IndexByte(s string, c byte) int

IndexByte returns the index of the first instance of c in s, or -1 if c is not present in s.

func IndexFuncSource

func IndexFunc(s string, f func(rune) bool) int

IndexFunc returns the index into s of the first Unicode code point satisfying f(c), or -1 if none do.

Example

package main

import (
	"fmt"
	"strings"
	"unicode"
)

func main() {
	f := func(c rune) bool {
		return unicode.Is(unicode.Han, c)
	}
	fmt.Println(strings.IndexFunc("Hello, 世界", f))
	fmt.Println(strings.IndexFunc("Hello, world", f))
}

func IndexRuneSource

func IndexRune(s string, r rune) int

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.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.IndexRune("chicken", 'k'))
	fmt.Println(strings.IndexRune("chicken", 'd'))
}

func JoinSource

func Join(a []string, sep string) string

Join concatenates the elements of a to create a single string. The separator string sep is placed between elements in the resulting string.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	s := []string{"foo", "bar", "baz"}
	fmt.Println(strings.Join(s, ", "))
}

func LastIndexSource

func LastIndex(s, sep string) int

LastIndex returns the index of the last instance of sep in s, or -1 if sep is not present in s.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Index("go gopher", "go"))
	fmt.Println(strings.LastIndex("go gopher", "go"))
	fmt.Println(strings.LastIndex("go gopher", "rodent"))
}

func LastIndexAnySource

func LastIndexAny(s, chars string) int

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 LastIndexByteSource

func LastIndexByte(s string, c byte) int

LastIndexByte returns the index of the last instance of c in s, or -1 if c is not present in s.

func LastIndexFuncSource

func LastIndexFunc(s string, f func(rune) bool) int

LastIndexFunc returns the index into s of the last Unicode code point satisfying f(c), or -1 if none do.

func MapSource

func Map(mapping func(rune) rune, s string) string

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.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	rot13 := func(r rune) rune {
		switch {
		case r >= 'A' && r <= 'Z':
			return 'A' + (r-'A'+13)%26
		case r >= 'a' && r <= 'z':
			return 'a' + (r-'a'+13)%26
		}
		return r
	}
	fmt.Println(strings.Map(rot13, "'Twas brillig and the slithy gopher..."))
}

func RepeatSource

func Repeat(s string, count int) string

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.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println("ba" + strings.Repeat("na", 2))
}

func ReplaceSource

func Replace(s, old, new string, n int) string

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.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Replace("oink oink oink", "k", "ky", 2))
	fmt.Println(strings.Replace("oink oink oink", "oink", "moo", -1))
}

func SplitSource

func Split(s, sep string) []string

Split slices s into all substrings separated by sep and returns a slice of the substrings between those separators. If sep is empty, Split splits after each UTF-8 sequence. It is equivalent to SplitN with a count of -1.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Printf("%q\n", strings.Split("a,b,c", ","))
	fmt.Printf("%q\n", strings.Split("a man a plan a canal panama", "a "))
	fmt.Printf("%q\n", strings.Split(" xyz ", ""))
	fmt.Printf("%q\n", strings.Split("", "Bernardo O'Higgins"))
}

func SplitAfterSource

func SplitAfter(s, sep string) []string

SplitAfter slices s into all substrings after each instance of sep and returns a slice of those substrings. If sep is empty, SplitAfter splits after each UTF-8 sequence. It is equivalent to SplitAfterN with a count of -1.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Printf("%q\n", strings.SplitAfter("a,b,c", ","))
}

func SplitAfterNSource

func SplitAfterN(s, sep string, n int) []string

SplitAfterN slices s into substrings after each instance of sep and returns a slice of those substrings. If sep is empty, SplitAfterN splits after each UTF-8 sequence. 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

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Printf("%q\n", strings.SplitAfterN("a,b,c", ",", 2))
}

func SplitNSource

func SplitN(s, sep string, n int) []string

SplitN slices s into substrings separated by sep and returns a slice of the substrings between those separators. If sep is empty, SplitN splits after each UTF-8 sequence. 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

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Printf("%q\n", strings.SplitN("a,b,c", ",", 2))
	z := strings.SplitN("a,b,c", ",", 0)
	fmt.Printf("%q (nil = %v)\n", z, z == nil)
}

func TitleSource

func Title(s string) string

Title returns a copy of the string s with all Unicode letters that begin words mapped to their title case.

BUG(rsc): The rule Title uses for word boundaries does not handle Unicode punctuation properly.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.Title("her royal highness"))
}

func ToLowerSource

func ToLower(s string) string

ToLower returns a copy of the string s with all Unicode letters mapped to their lower case.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.ToLower("Gopher"))
}

func ToLowerSpecialSource

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, giving priority to the special casing rules.

func ToTitleSource

func ToTitle(s string) string

ToTitle returns a copy of the string s with all Unicode letters mapped to their title case.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.ToTitle("loud noises"))
	fmt.Println(strings.ToTitle("хлеб"))
}

func ToTitleSpecialSource

func ToTitleSpecial(c unicode.SpecialCase, s string) string

ToTitleSpecial returns a copy of the string s with all Unicode letters mapped to their title case, giving priority to the special casing rules.

func ToUpperSource

func ToUpper(s string) string

ToUpper returns a copy of the string s with all Unicode letters mapped to their upper case.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.ToUpper("Gopher"))
}

func ToUpperSpecialSource

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, giving priority to the special casing rules.

func TrimSource

func Trim(s string, cutset string) string

Trim returns a slice of the string s with all leading and trailing Unicode code points contained in cutset removed.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Printf("[%q]", strings.Trim(" !!! Achtung! Achtung! !!! ", "! "))
}

func TrimFuncSource

func TrimFunc(s string, f func(rune) bool) string

TrimFunc returns a slice of the string s with all leading and trailing Unicode code points c satisfying f(c) removed.

func TrimLeftSource

func TrimLeft(s string, cutset string) string

TrimLeft returns a slice of the string s with all leading Unicode code points contained in cutset removed.

func TrimLeftFuncSource

func TrimLeftFunc(s string, f func(rune) bool) string

TrimLeftFunc returns a slice of the string s with all leading Unicode code points c satisfying f(c) removed.

func TrimPrefixSource

func TrimPrefix(s, prefix string) string

TrimPrefix returns s without the provided leading prefix string. If s doesn't start with prefix, s is returned unchanged.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	var s = "Goodbye,, world!"
	s = strings.TrimPrefix(s, "Goodbye,")
	s = strings.TrimPrefix(s, "Howdy,")
	fmt.Print("Hello" + s)
}

func TrimRightSource

func TrimRight(s string, cutset string) string

TrimRight returns a slice of the string s, with all trailing Unicode code points contained in cutset removed.

func TrimRightFuncSource

func TrimRightFunc(s string, f func(rune) bool) string

TrimRightFunc returns a slice of the string s with all trailing Unicode code points c satisfying f(c) removed.

func TrimSpaceSource

func TrimSpace(s string) string

TrimSpace returns a slice of the string s, with all leading and trailing white space removed, as defined by Unicode.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	fmt.Println(strings.TrimSpace(" \t\n a lone gopher \n\t\r\n"))
}

func TrimSuffixSource

func TrimSuffix(s, suffix string) string

TrimSuffix returns s without the provided trailing suffix string. If s doesn't end with suffix, s is returned unchanged.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	var s = "Hello, goodbye, etc!"
	s = strings.TrimSuffix(s, "goodbye, etc!")
	s = strings.TrimSuffix(s, "planet")
	fmt.Print(s, "world!")
}

type ReaderSource

A Reader implements the io.Reader, io.ReaderAt, io.Seeker, io.WriterTo, io.ByteScanner, and io.RuneScanner interfaces by reading from a string.

type Reader struct {
        // contains filtered or unexported fields
}

func NewReaderSource

func NewReader(s string) *Reader

NewReader returns a new Reader reading from s. It is similar to bytes.NewBufferString but more efficient and read-only.

func (*Reader) LenSource

func (r *Reader) Len() int

Len returns the number of bytes of the unread portion of the string.

func (*Reader) ReadSource

func (r *Reader) Read(b []byte) (n int, err error)

func (*Reader) ReadAtSource

func (r *Reader) ReadAt(b []byte, off int64) (n int, err error)

func (*Reader) ReadByteSource

func (r *Reader) ReadByte() (byte, error)

func (*Reader) ReadRuneSource

func (r *Reader) ReadRune() (ch rune, size int, err error)

func (*Reader) ResetSource

func (r *Reader) Reset(s string)

Reset resets the Reader to be reading from s.

func (*Reader) SeekSource

func (r *Reader) Seek(offset int64, whence int) (int64, error)

Seek implements the io.Seeker interface.

func (*Reader) SizeSource

func (r *Reader) Size() int64

Size returns the original length of the underlying string. Size is the number of bytes available for reading via ReadAt. The returned value is always the same and is not affected by calls to any other method.

func (*Reader) UnreadByteSource

func (r *Reader) UnreadByte() error

func (*Reader) UnreadRuneSource

func (r *Reader) UnreadRune() error

func (*Reader) WriteToSource

func (r *Reader) WriteTo(w io.Writer) (n int64, err error)

WriteTo implements the io.WriterTo interface.

type ReplacerSource

Replacer replaces a list of strings with replacements. It is safe for concurrent use by multiple goroutines.

type Replacer struct {
        // contains filtered or unexported fields
}

func NewReplacerSource

func NewReplacer(oldnew ...string) *Replacer

NewReplacer returns a new Replacer from a list of old, new string pairs. Replacements are performed in order, without overlapping matches.

Example

package main

import (
	"fmt"
	"strings"
)

func main() {
	r := strings.NewReplacer("<", "&lt;", ">", "&gt;")
	fmt.Println(r.Replace("This is <b>HTML</b>!"))
}

func (*Replacer) ReplaceSource

func (r *Replacer) Replace(s string) string

Replace returns a copy of s with all replacements performed.

func (*Replacer) WriteStringSource

func (r *Replacer) WriteString(w io.Writer, s string) (n int, err error)

WriteString writes s to w with all replacements performed.

Bugs

☞
The rule Title uses for word boundaries does not handle Unicode punctuation properly.