string package in Golang

Go language provides a string package that holds different types of functions to manipulate UTF-8 encoded strings. To access the function of the string package you need to import a string package in your program with the help of the import keyword.  

Function	Description
func Compare	This function is used to return an integer comparing two strings lexicographically.
func Contains	This function is used to check whether substr is within s or not.
func ContainsAny	This function is used to check whether any Unicode code points in chars are within s or not.
func ContainsRune	This function is used to check whether the Unicode code point r is within s or not.
func Count	This function is used to count the number of non-overlapping instances of substr in given string s.
func EqualFold	This function is used to check whether s and t, interpreted as UTF-8 strings, are equal under Unicode case-folding, which is a more general form of case-insensitivity or not.
func Fields	This function is used to splits the given 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	This function is used to splits the string s at each run of Unicode code points c satisfying f(c) and returns an array of slices of s.
func HasPrefix	This function is used to check whether the string s begins with prefix or not.
HasSuffix	This function is used to check whether the string s ends with suffix or not.
func Index	This function is used to returns the index of the first instance of substr in s or -1 if substr is not present in s.
func IndexAny	This function is used to 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	This function is used to returns the index of the first instance of c in s, or -1 if c is not present in s.
func IndexFunc	This function is used to returns the index into s of the first Unicode code point satisfying f(c) or -1 if none do.
func IndexRune	This function is used to returns the index of the first instance of the Unicode code point r, or -1 if rune is not present in s.
func Join	This function is used to concatenate the elements of its first argument to create a single string.
func LastIndex	This function is used to returns the index of the last instance of substr in s, or -1 if substr is not present in s.
func LastIndexAny	This function is used to 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	This function is used to returns the index of the last instance of c in s, or -1 if c is not present in s.
func LastIndexFunc	This function is used to returns the index into s of the last Unicode code point satisfying f(c), or -1 if none do.
func Map	This function is used to returns a copy of the string s with all its characters modified according to the mapping function.
func Repeat	This function is used to returns a new string consisting of count copies of the string s.
func Replace	This function is used to returns a copy of the string s with the first n non-overlapping instances of old replaced by new.
func ReplaceAll	This function is used to returns a copy of the string s with all non-overlapping instances of old replaced by new.
func Split	This function is used to slices s into all substrings separated by sep and returns a slice of the substrings between those separators.
func SplitAfter	This function is used to slices s into all substrings after each instance of sep and returns a slice of those substrings.
func SplitAfterN	This function is used to slices s into substrings after each instance of sep and returns a slice of those substrings.
func SplitN	This function is used to slices s into substrings separated by sep and returns a slice of the substrings between those separators.
func Title	This function is used to returns a copy of the string s with all Unicode letters that begin words mapped to their Unicode title case.
func ToLower	This method is used to returns s with all Unicode letters mapped to their lower case.
func ToLowerSpecial	This function is used to 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	This function is used to returns a copy of the string s with all Unicode letters mapped to their Unicode title case.
func ToTitleSpecial	This function is used to 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 ToUpper	This function is used to returns s with all Unicode letters mapped to their upper case.
func ToUpperSpecial	This function is used to 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	This function is used to 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	This function is used to returns a slice of the given string with all leading and trailing Unicode code points contained in cutset removed.
func TrimFunc	This function is used to returns a slice of the given string with all leading and trailing Unicode code points c satisfying f(c) removed.
func TrimLeft	This method is used to returns a slice of the given string with all leading Unicode code points contained in cutset removed.
func TrimLeftFunc	This function is used to returns a slice of the given string with all leading Unicode code points c satisfying f(c) removed.
func TrimPrefix	This function is used to returns s without the provided leading prefix string. If s doesn’t start with prefix, s is returned unchanged.
func TrimRight	This function is used to returns a slice of the given string, with all trailing Unicode code points contained in cutset removed.
func TrimRightFunc	This function is used to returns a slice of the given string with all trailing Unicode code points c satisfying f(c) removed.
func TrimSpace	This function is used to returns a slice of given the string, with all leading and trailing white space removed, as defined by Unicode.
func TrimSuffix	This function is used to returns s without the provided trailing suffix string.

type Builder

Method	Description
func (*Builder) Cap	This method is used to returns the capacity of the builder’s underlying byte slice.
func (*Builder) Grow	This method is used to grows b’s capacity if necessary, to guarantee space for another n bytes.
func (*Builder) Len	This method is used to returns the number of accumulated bytes.
func (*Builder) Reset	This method is used to resets the Builder to be empty.
func (*Builder) String	This method is used to returns the accumulated string.
func (*Builder) Write	This method is used to appends the contents of p to b’s buffer.
func (*Builder) WriteByte	This method is used to appends the byte c to b’s buffer.
func (*Builder) WriteRune	This method is used to appends the UTF-8 encoding of Unicode code point r to b’s buffer.
func (*Builder) WriteString	This method is used to appends the contents of str to b’s buffer. It returns the length of str and a nil error.

type Reader

Method	Description
func NewReader	This function is used to returns a new Reader reading from s.
func (*Reader) Len	This method is used to returns the number of bytes of the unread portion of the string.
func (*Reader) Reset	This method is used to resets the Reader to be reading from s.
func (*Reader) Seek	This method is used to implements the io.Seeker interface.
func (*Reader) Size	This method is used to returns the original length of the underlying string.
func (*Reader) WriteTo	This method is used to implements the io.WriterTo interface.

type Replacer 

Method	Description
func NewReplacer	This function is used to returns a new Replacer from a list of old, new string pairs.
func (*Replacer) Replace	This method is used to returns a copy of s with all replacements performed.
func (*Replacer) WriteString	This method is used to writes s to w with all replacements performed.

Example 1:

Go

// Golang program to illustrate the use of
// the strings.Compare() Function
package main

import (
    "fmt"
    "strings"
)

func main() {

    var r1 = "Geeks"
    var r2 = "GeeksforGeeks"
    var r3 = "Geeks"

    // using the function
    fmt.Println(strings.Compare(r1, r2))
    fmt.Println(strings.Compare(r2, r3))
    fmt.Println(strings.Compare(r3, r1))

}

Output:

-1
1
0

Example 2:

Go

// Golang program to illustrate
// the strings.IndexAny() Function
package main

import (
    "fmt"
    "strings"
)

// Main function
func main() {

    // using the function
    fmt.Println(strings.IndexAny("Hey GFG?", "y"))

}

Output:

2

Example 3 :

Go

package main

import (
    "fmt"
    "strings"
)

func main() {
    //fmt.Println("Bhavya")
    var c string
    c = "bhavya"
    d := strings.Replace(c, "h", "v", 1)
    e := strings.Contains(c, "bha")
    f := strings.Count(c, "a")
    g := strings.Repeat(c, 5)
    h := strings.Split(c, "a")
    i := strings.ToLower(c)
    j := strings.ToUpper(c)
    k := strings.ToTitle(c)
    l := strings.HasPrefix(c, "BHa")
    m := strings.HasSuffix(c, "vy")
    n := strings.ReplaceAll(c, "a", "b")
    o := strings.Compare(c, "bhavya")
    p := strings.Trim(c, "a")
    r := strings.EqualFold(c, "BHAVYA")
    s := strings.IndexAny(c, "b")
    t := strings.Index(c, "a")
    u := strings.EqualFold("bhavya", "BHAVYA")
    v := strings.SplitN("b.h*a.v*y.a", "*", 3)
    fmt.Println(d, e, f, g, h, i, j, k, l, m, n, o, p,r, s, t, u, v)
}

Output

bvavya true 2 bhavyabhavyabhavyabhavyabhavya [bh vy ] bhavya BHAVYA BHAVYA false false bhbvyb 0 bhavy true 0 2 true [b.h a.v y.a]