Go strings API Reference

`strings`

10 methods

Package strings implements simple functions to manipulate UTF-8 encoded strings.

strings.Contains(s, substr string) bool

Return true if substr is within s.

Parameters

Name	Type	Description
s	string	String to search.
substr	string	Substring to find.

Returns

bool

Example

package main
import ("fmt"; "strings")
func main() {
    fmt.Println(strings.Contains("hello", "ell"))  // true
    fmt.Println(strings.Contains("hello", "xyz"))  // false
}

strings.HasPrefix(s, prefix string) bool

Return true if s begins with prefix.

Parameters

Name	Type	Description
s	string	String to check.
prefix	string	Prefix to test.

Returns

bool

Example

strings.HasPrefix("hello.go", "hello")  // true
strings.HasPrefix("hello.go", ".go")    // false

strings.HasSuffix(s, suffix string) bool

Return true if s ends with suffix.

Parameters

Name	Type	Description
s	string	String to check.
suffix	string	Suffix to test.

Returns

bool

Example

strings.HasSuffix("hello.go", ".go")  // true
strings.HasSuffix("hello.go", "hello")  // false

strings.Index(s, substr string) int

Return the index of the first instance of substr in s, or -1 if not present.

Parameters

Name	Type	Description
s	string	String to search.
substr	string	Substring to find.

Returns

int

Example

strings.Index("hello", "ll")  // 2
strings.Index("hello", "z")   // -1

strings.Split(s, sep string) []string

Split s into substrings separated by sep. Returns []string.

Parameters

Name	Type	Description
s	string	String to split.
sep	string	Separator.

Returns

[]string

Example

strings.Split("a,b,c", ",")  // ["a", "b", "c"]
strings.Split("hello", "")    // ["h","e","l","l","o"]

strings.Join(elems []string, sep string) string

Concatenate the elements of elems with sep between each.

Parameters

Name	Type	Description
elems	[]string	Strings to join.
sep	string	Separator.

Returns

string

Example

strings.Join([]string{"a", "b", "c"}, "-")  // "a-b-c"
strings.Join([]string{"x"}, ",")            // "x"

strings.Replace(s, old, new string, n int) string

Return s with the first n non-overlapping instances of old replaced by new. n < 0 means no limit.

Parameters

Name	Type	Description
s	string	Source string.
old	string	Substring to replace.
new	string	Replacement.
n	int	Max replacements (-1 for all).

Returns

string

Example

strings.Replace("a-b-c", "-", "_", 1)   // "a_b-c"
strings.Replace("a-b-c", "-", "_", -1)  // "a_b_c"

strings.ToUpper(s string) string

Return s with all Unicode letters mapped to upper case.

Parameters

Name	Type	Description
s	string	Source string.

Returns

string

Example

strings.ToUpper("hello")  // "HELLO"
strings.ToUpper("café")   // "CAFÉ"

strings.ToLower(s string) string

Return s with all Unicode letters mapped to lower case.

Parameters

Name	Type	Description
s	string	Source string.

Returns

string

Example

strings.ToLower("HELLO")  // "hello"
strings.ToLower("CAFÉ")   // "café"

strings.Trim(s, cutset string) string

Return s with all leading and trailing characters in cutset removed.

Parameters

Name	Type	Description
s	string	Source string.
cutset	string	Characters to trim.

Returns

string

Example

strings.Trim("  hi  ", " ")   // "hi"
strings.Trim("xxhelloxx", "x")  // "hello"

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