Package strings

fmt.Println(strings.Contains("seafood", "foo"))
fmt.Println(strings.Contains("seafood", "bar"))
fmt.Println(strings.Contains("seafood", ""))
fmt.Println(strings.Contains("", ""))

Output:

true
false
true
true

func ContainsAny

func ContainsAny(s, chars string) bool

ContainsAny returns true if any Unicode code points in chars are within s.

▹ Example

▾ Example

Code:

fmt.Println(strings.ContainsAny("team", "i"))
fmt.Println(strings.ContainsAny("failure", "u & i"))
fmt.Println(strings.ContainsAny("foo", ""))
fmt.Println(strings.ContainsAny("", ""))

Output:

false
true
false
false

func ContainsRune

func ContainsRune(s string, r rune) bool

ContainsRune returns true if the Unicode code point r is within s.

func Count

func Count(s, sep string) int

Count counts the number of non-overlapping instances of sep in s.

▹ Example

▾ Example

Code:

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

Output:

3
5

func EqualFold

func EqualFold(s, t string) bool

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

▹ Example

▾ Example

Code:

fmt.Println(strings.EqualFold("Go", "go"))

Output:

true

func Fields

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

▾ Example

Code:

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

Output:

Fields are: ["foo" "bar" "baz"]

func FieldsFunc

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

▾ Example

Code:

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

Output:

Fields are: ["foo1" "bar2" "baz3"]

func HasPrefix

func HasPrefix(s, prefix string) bool

HasPrefix tests whether the string s begins with prefix.

func HasSuffix

func HasSuffix(s, suffix string) bool

HasSuffix tests whether the string s ends with suffix.

func Index

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

▾ Example

Code:

fmt.Println(strings.Index("chicken", "ken"))
fmt.Println(strings.Index("chicken", "dmr"))

Output:

4
-1

func IndexAny

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

▾ Example

Code:

fmt.Println(strings.IndexAny("chicken", "aeiouy"))
fmt.Println(strings.IndexAny("crwth", "aeiouy"))

Output:

2
-1

func IndexByte

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 IndexFunc

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

▾ Example

Code:

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))

Output:

7
-1

func IndexRune

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.

▹ Example

▾ Example

Code:

fmt.Println(strings.IndexRune("chicken", 'k'))
fmt.Println(strings.IndexRune("chicken", 'd'))

Output:

4
-1

func Join

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

▾ Example

Code:

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

Output:

foo, bar, baz

func LastIndex

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

▾ Example

Code:

fmt.Println(strings.Index("go gopher", "go"))
fmt.Println(strings.LastIndex("go gopher", "go"))
fmt.Println(strings.LastIndex("go gopher", "rodent"))

Output:

0
3
-1

func LastIndexAny

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 LastIndexFunc

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 Map

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

▾ Example

Code:

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..."))

Output:

'Gjnf oevyyvt naq gur fyvgul tbcure...

func Repeat

func Repeat(s string, count int) string

Repeat returns a new string consisting of count copies of the string s.

▹ Example

▾ Example

Code:

fmt.Println("ba" + strings.Repeat("na", 2))

Output:

banana

func Replace

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

▾ Example

Code:

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

Output:

oinky oinky oink
moo moo moo

func Split

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

▾ Example

Code:

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"))

Output:

["a" "b" "c"]
["" "man " "plan " "canal panama"]
[" " "x" "y" "z" " "]
[""]

func SplitAfter

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

▾ Example

Code:

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

Output:

["a," "b," "c"]

func SplitAfterN

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

▾ Example

Code:

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

Output:

["a," "b,c"]

func SplitN

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

▾ Example

Code:

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)

Output:

["a" "b,c"]
[] (nil = true)

func Title

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

▹ Example

▾ Example

Code:

fmt.Println(strings.Title("her royal highness"))

Output:

Her Royal Highness

func ToLower

func ToLower(s string) string

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

▹ Example

▾ Example

Code:

fmt.Println(strings.ToLower("Gopher"))

Output:

gopher

func ToLowerSpecial

func ToLowerSpecial(_case 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 ToTitle

func ToTitle(s string) string

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

▹ Example

▾ Example

Code:

fmt.Println(strings.ToTitle("loud noises"))
fmt.Println(strings.ToTitle("хлеб"))

Output:

LOUD NOISES
ХЛЕБ

func ToTitleSpecial

func ToTitleSpecial(_case 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 ToUpper

func ToUpper(s string) string

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

▹ Example

▾ Example

Code:

fmt.Println(strings.ToUpper("Gopher"))

Output:

GOPHER

func ToUpperSpecial

func ToUpperSpecial(_case 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 Trim

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

▾ Example

Code:

fmt.Printf("[%q]", strings.Trim(" !!! Achtung! Achtung! !!! ", "! "))

Output:

["Achtung! Achtung"]

func TrimFunc

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 TrimLeft

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 TrimLeftFunc

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 TrimPrefix

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

▾ Example

Code:

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

Output:

Hello, world!

func TrimRight

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 TrimRightFunc

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 TrimSpace

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

▾ Example

Code:

fmt.Println(strings.TrimSpace(" \t\n a lone gopher \n\t\r\n"))

Output:

a lone gopher

func TrimSuffix

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

▾ Example

Code:

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

Output:

Hello, world!

type Reader

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

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

func NewReader

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) Len

func (r *Reader) Len() int

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

func (*Reader) Read

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

func (*Reader) ReadAt

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

func (*Reader) ReadByte

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

func (*Reader) ReadRune

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

func (*Reader) Seek

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

Seek implements the io.Seeker interface.

func (*Reader) UnreadByte

func (r *Reader) UnreadByte() error

func (*Reader) UnreadRune

func (r *Reader) UnreadRune() error

func (*Reader) WriteTo

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

WriteTo implements the io.WriterTo interface.

type Replacer

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

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

func NewReplacer

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

▾ Example

Code:

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

Output:

This is &lt;b&gt;HTML&lt;/b&gt;!

func (*Replacer) Replace

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

Replace returns a copy of s with all replacements performed.

func (*Replacer) WriteString

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

WriteString writes s to w with all replacements performed.

Package strings

Overview ▹

Overview ▾

Index ▹

Index ▾

Examples

Package files

Internal call graph ▹

Internal call graph ▾

func Contains

func ContainsAny

func ContainsRune

func Count

func EqualFold

func Fields

func FieldsFunc

func HasPrefix

func HasSuffix

func Index

func IndexAny

func IndexByte

func IndexFunc

func IndexRune

func Join

func LastIndex

func LastIndexAny

func LastIndexFunc

func Map

func Repeat

func Replace

func Split

func SplitAfter

func SplitAfterN

func SplitN

func Title

func ToLower

func ToLowerSpecial

func ToTitle

func ToTitleSpecial

func ToUpper

func ToUpperSpecial

func Trim

func TrimFunc

func TrimLeft

func TrimLeftFunc

func TrimPrefix

func TrimRight

func TrimRightFunc

func TrimSpace

func TrimSuffix

type Reader

func NewReader

func (*Reader) Len

func (*Reader) Read

func (*Reader) ReadAt

func (*Reader) ReadByte

func (*Reader) ReadRune

func (*Reader) Seek

func (*Reader) UnreadByte

func (*Reader) UnreadRune

func (*Reader) WriteTo

type Replacer

func NewReplacer

func (*Replacer) Replace

func (*Replacer) WriteString