How to split a string into a slice in Go

Created Apr 14, 2022 at 11:11

Modified Apr 14, 2022 at 11:15

Using strings.Split Function

Use the strings.Split function to split a string into its comma separated values.

package main

import (
  "fmt"
  "strings"
)

func main() {

  s := "Japan,Germany"

  // func Split(s, sep string) []string
  slice := strings.Split(s, ",")
  fmt.Printf("%q\n", slice)

  // sep is empty
  slice = strings.Split(s, "")
  fmt.Printf("%q\n", slice)

}

["Japan" "Germany"]
["J" "a" "p" "a" "n" "," "G" "e" "r" "m" "a" "n" "y"]

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.

Using strings.Fields Function

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. For example,

package main

import (
  "fmt"
  "strings"
)

func main() {

  s := "Japan Germany"

  // var asciiSpace = [256]uint8{'\t': 1, '\n': 1, '\v': 1, '\f': 1, '\r': 1, ' ': 1}
  // func Fields(s string) []string
  slice := strings.Fields(s)
  fmt.Printf("%q\n", slice)

}

["Japan" "Germany"]

Using the regexp Split Function

Split slices s into substrings separated by the expression and returns a slice of the substrings between those expression matches. The count determines the number of substrings to return. if n < 0, it returns all substrings. For example,

package main

import (
  "fmt"
  "regexp"
)

func main() {

  s := "abaabaccad"

  a := regexp.MustCompile(`a`)

  // func (re *Regexp) Split(s string, n int) []string
  fmt.Printf("%q\n", a.Split(s, -1))
  fmt.Printf("%q\n", a.Split(s, 0))
  fmt.Printf("%q\n", a.Split(s, 1))

}

["" "b" "" "b" "cc" "d"]
[]
["abaabaccad"]

You can use regexp.Split to split a string into a slice of strings with the regex pattern as the delimiter.

package main

import (
  "fmt"
  "regexp"
)

func main() {

  s := "how789to1234split"

  a := regexp.MustCompile(`[0-9]+`)

  fmt.Printf("%q\n", a.Split(s, -1))

}