How to remove redundant spaces/whitespace from a string in Golang?

Question

I was wondering how to remove:

• All leading/trailing whitespace or new-line characters, null characters, etc.
• Any redundant spaces within a string (ex. "hello[space][space]world" would be converted to "hello[space]world")

Is this possible with a single Regex, with unicode support for international space characters, etc.?

Answer 1

You can get quite far just using the strings package as strings.Fields does most of the work for you:

package main  import (     "fmt"     "strings" )  func standardizeSpaces(s string) string {     return strings.Join(strings.Fields(s), " ") }  func main() {     tests := []string{" Hello,   World  ! ", "Hello,\tWorld ! ", " \t\n\t Hello,\tWorld\n!\n\t"}     for _, test := range tests {         fmt.Println(standardizeSpaces(test))     } } // "Hello, World !" // "Hello, World !" // "Hello, World !" 

Answer 2

It seems that you might want to use both \s shorthand character class and \p{Zs} Unicode property to match Unicode spaces. However, both steps cannot be done with 1 regex replacement as you need two different replacements, and the ReplaceAllStringFunc only allows a whole match string as argument (I have no idea how to check which group matched).

Thus, I suggest using two regexps:

• ^[\s\p{Zs}]+|[\s\p{Zs}]+$ - to match all leading/trailing whitespace
• [\s\p{Zs}]{2,} - to match 2 or more whitespace symbols inside a string

Sample code:

package main  import (     "fmt"     "regexp" )  func main() {     input := "   Text   More here     "     re_leadclose_whtsp := regexp.MustCompile(`^[\s\p{Zs}]+|[\s\p{Zs}]+$`)     re_inside_whtsp := regexp.MustCompile(`[\s\p{Zs}]{2,}`)     final := re_leadclose_whtsp.ReplaceAllString(input, "")     final = re_inside_whtsp.ReplaceAllString(final, " ")     fmt.Println(final) }