Remove non-letters from a string

From CodeCodex

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<DPL>

category=String shownamespace=false </DPL>

Contents

[edit] Implementations

[edit] Java

This code removes common symbols and numbers from a string, returning letters only. (Note, not all symbols are included.) 

static String lettersOnly(String s) {
   return s.replaceAll("[^a-zA-Z]","");
}

[edit] C

if buff's content is: "15+41-2Hel54lo **1212 Wor2ld! Ho5w Are 6996 Yo7u?" then the content of buff_02 will be: "HelloWorldHowAreYou" 

#include <string.h>

while (i != strlen (buff))
{
        if ((buff[i] >= 65) && (buff[i] <= 90) || (buff[i] >= 97) && (buff[i] <= 122))
        {
                buff_02[j] = buff[i];
                i++;
                j++;
        }
        else
        {
                i++;
        }
}

[edit] JavaScript


var s = "how19 a*re 254y**ou?";

document.write(s.replace(/[^A-Za-z]/g, ""));

[edit] OCaml

# let remove_nonalpha = Str.global_replace (Str.regexp "[^a-zA-Z]+") "";;
val remove_nonalpha : string -> string = <fun>

For example: 

# remove_nonalpha "133t H4x0r";;
- : string = "tHxr"

[edit] Perl


s{[\W\d_]}{}g; # remove all non-word characters and digits and underscores

[edit] PHP


$result = preg_replace('/[^A-Za-z]/', '', $string);

[edit] Python


s = "hello world! how are you? 0"

# Short version
print filter(lambda c: c.isalpha(), s)

# Faster version for long ASCII strings:
id_tab = "".join(map(chr, xrange(256)))
tostrip = "".join(c for c in id_tab if c.isalpha())
print s.translate(id_tab, tostrip)

# Using regular expressions
print re.sub("[^A-Za-z]", "", s)

[edit] Tcl 

proc remove_non_ascii_letters s {regsub -all {[^a-zA-Z]} $s ""}

remove_non_ascii_letters "hello world! how are you? 0é" ;# -> helloworldhowareyou

[edit] Visual Basic

Public Function ReturnAlpha(ByVar sString As String) As String
Dim i As Integer
For i = 1 To Len(sString)
    If Mid(sString, i, 1) Like "[A-Za-z]" Then
        ReturnAlpha = ReturnAlpha + Mid(sString, i, 1)
    End If
Next i
End Function

[edit] WinBatch

; Remove non-letters from a string, assuming space as non-letter character.

strString = "15+41-2Hel54lo **1212 Wor2ld! Ho5w Are 6996 Yo7u?"

; Example 1
strClean1 = StrClean (strString, "0123456789+-*/!?.,;:~@ ", "", @TRUE, 1) 
; strClean1 = "HelloWorldHowAreYou"

; Example 2
strClean2 = StrClean (strString, "abcdefghijklmnopqrstuvwxyz", "", @FALSE, 2) 
; strClean2 = "HelloWorldHowAreYou"

; Example 3
objRegExp = ObjectCreate ("VBScript.RegExp")
objRegExp.IgnoreCase = @TRUE
objRegExp.MultiLine = @FALSE
objRegExp.Global = @TRUE
objRegExp.Pattern = "[^a-z]"
strClean3 = objRegExp.Replace(strString, "") 
objRegExp = 0
; strClean3 = "HelloWorldHowAreYou"

Exit
; This code example was written by Detlev Dalitz.

[edit] Zsh

s="Hello, World! How are you? 1... 2... 3..."
print "${s//[^a-zA-Z]/}"
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