Strip control codes and extended characters from a string: Difference between revisions

=={{header|Go}}==

Go works for ASCII and non-ASCII systems. The first pair of functions below interpret strings as byte strings, presumably useful for strings consisting of ASCII and 8-bit extended ASCII data. The second pair of functions interpret strings as UTF-8.

<lang go>package main

import (

"fmt"

"strings"

)

// two byte-oriented functions identical except for operator comparing c to 127.

func stripCtlFromBytes(str string) string {

b := make([]byte, len(str))

var bl int

for i := 0; i < len(str); i++ {

c := str[i]

if c >= 32 && c != 127 {

b[bl] = c

bl++

}

}

return string(b[:bl])

}

func stripCtlAndExtFromBytes(str string) string {

b := make([]byte, len(str))

var bl int

for i := 0; i < len(str); i++ {

c := str[i]

if c >= 32 && c < 127 {

b[bl] = c

bl++

}

}

return string(b[:bl])

}

// two UTF-8 functions identical except for operator comparing c to 127

func stripCtlFromUTF8(str string) string {

return strings.Map(func(rune int) int {

if rune >= 32 && rune != 127 {

return rune

}

return -1

}, str)

}

func stripCtlAndExtFromUTF8(str string) string {

return strings.Map(func(rune int) int {

if rune >= 32 && rune < 127 {

return rune

}

return -1

}, str)

}

const src = "déjà vu" + // precomposed unicode

"\n\000\037 \041\176\177\200\377\n" + // various boundary cases

"as⃝df̅" // unicode combining characters

func main() {

fmt.Println("source text:")

fmt.Println(src, "\n")

fmt.Println("as bytes, stripped of control codes:")

fmt.Println(stripCtlFromBytes(src), "\n")

fmt.Println("as bytes, stripped of control codes and extended characters:")

fmt.Println(stripCtlAndExtFromBytes(src), "\n")

fmt.Println("as UTF-8, stripped of control codes:")

fmt.Println(stripCtlFromUTF8(src), "\n")

fmt.Println("as UTF-8, stripped of control codes and extended characters:")

fmt.Println(stripCtlAndExtFromUTF8(src))

}

</lang>

Output: (varies with display configuration)

<pre>

source text:

déjà vu

� !~��

as⃝df̅

as bytes, stripped of control codes:

déjà vu !~��as⃝df̅

as bytes, stripped of control codes and extended characters:

dj vu !~asdf

as UTF-8, stripped of control codes:

déjà vu !~��as⃝df̅

as UTF-8, stripped of control codes and extended characters:

dj vu !~asdf

</pre>