Golang : Remove characters from string example

Problem:

You have a string and you want to remove certain characters from the string base on a set of characters. You've tried using strings.Replace() function to remove the unwanted characters, but you found out that it removes one character at a time, not a set of characters. To remove a set of characters with strings.Replace() function requires looping and can be inefficient. Is there a better way to remove a set of characters from a string?

Solution:

Combine strings.Map() and strings.IndexRune() functions to remove a set of unwanted characters from the string.

Here you go!

 package main

 import (
 "fmt"
 "strings"
 )

 func removeCharacters(input string, characters string) string {
 filter := func(r rune) rune {
 if strings.IndexRune(characters, r) < 0 {
 return r
 }
 return -1
 }

 return strings.Map(filter, input)

 }

 func main() {

 str := "你好吗? 我好! 好我好!? 你好好!"
 stripped := strings.Replace(str, "我好", "", -1) // Replace will work with a single unicode
 fmt.Println("Before : ", str)
 fmt.Println("After : ", stripped)

 str = "Happy Go Lucky!"
 stripped = strings.Replace(str, "a", "", -1) // only works with a single character
 fmt.Println("Before : ", str)
 fmt.Println("After : ", stripped)

 str = "Happy Go Lucky!"
 stripped = strings.Replace(str, "aGo", "", -1) // but NOT with a set of characters
 fmt.Println("Before : ", str)
 fmt.Println("After : ", stripped)

 fmt.Println("-------------------------------------------------")
 str = "你好吗? 我好! 好我好!? 你好好!"
 stripped = removeCharacters(str, "我好") // now with remove/strip a set of unicode characters
 fmt.Println("Before : ", str)
 fmt.Println("After : ", stripped)

 str = "Happy Go Lucky!"
 stripped = removeCharacters(str, "aGo") // will work with a set of characters
 fmt.Println("Before : ", str)
 fmt.Println("After : ", stripped)

 }

Output:

Before : 你好吗? 我好! 好我好!? 你好好!

After : 你好吗? ! 好!? 你好好!

Before : Happy Go Lucky!

After : Hppy Go Lucky!

Before : Happy Go Lucky!

After : Happy Go Lucky!

---

Before : 你好吗? 我好! 好我好!? 你好好!

After : 你吗? ! !? 你!

Before : Happy Go Lucky!

After : Hppy Lucky!

References:

https://golang.org/pkg/strings/#IndexRune

https://golang.org/pkg/strings/#Map

https://www.socketloop.com/tutorials/golang-remove-dashes-or-any-character-from-string