Replace all characters except letters, numbers, spaces and underscores

Question

I am looking to replace all characters in a string except letters, numbers, spaces and underscores.

Could someone please provide a example?

What examples have you found that don't work? How do they not work? — BoltClock, Jun 22 '11 at 15:13
I will also add that for string manipulation questions of all sorts, it helps to get the right answer if you provide a concrete example or two of what you would have going into the manipulation and what you would like to have coming out of the manipulation. — EBGreen, Jun 22 '11 at 15:15

score 91 · Accepted Answer · answered Jun 22 '11 at 15:14

91

I normally use something like:

$string = preg_replace("/[^ \w]+/", "", $string);

That replaces all non-space and non-word characters with nothing.

answered Jun 22 '11 at 15:14

jeroen

14

you should use single quotes for regex in PHP `preg_replace('/[^ \w]+/', '', $string)` double quotes with \ in them can result in unexpected behaviour – DarkMukke Jan 26 '13 at 11:09
you should say all non-english characters, for example it removes Cyrillic symbols too – Eugene May 20 '18 at 15:57

score 30 · Answer 2 · edited Jan 10 '14 at 05:50

30

[^0-9a-zA-Z_\s]

is what you want to replace.

edited Jan 10 '14 at 05:50

Funk Forty Niner

answered Jun 22 '11 at 15:14

Raffael

18

This one helped me on a similar issue. Thanks! (For others reading this, don't forget to wrap it in slashes like this: `$new_string=preg_replace('/[^0-9a-zA-Z_]/',"",$old_string)` I took out the \s because I didn't need to allow spaces. – TecBrat Apr 18 '12 at 18:39
1

`\s` does not mean space always... – Vishal Kumar Sahu Feb 09 '17 at 09:37

score 8 · Answer 3 · answered Jun 22 '11 at 15:14

8

<?php
$string = 'April 15, 2003';
$pattern = '/[^\w ]+/';
$replacement = '';
echo preg_replace($pattern, $replacement, $string);
?>

answered Jun 22 '11 at 15:14

agent-j

3 Answers3