# Stripping non alphanumeric characters

**URL:** <https://www.ruby-forum.com/t/stripping-non-alphanumeric-characters/147441>\
**Category:** Ruby\
**Created:** [September 1, 2008, 9:42pm UTC](https://www.ruby-forum.com/t/stripping-non-alphanumeric-characters/147441 "2008-09-01T21:42:52Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![benjohnson](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/3ec8ea/32.png) [@benjohnson](https://www.ruby-forum.com/u/benjohnson)\
**Post date:** [September 1, 2008, 9:42pm UTC](https://www.ruby-forum.com/t/stripping-non-alphanumeric-characters/147441/1 "2008-09-01T21:42:52Z")

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I know this is a noob question. What would be the best / most efficient  
way to replace all non alphanumeric characters in a string?

Thanks for your help.

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**Author:** ![benjohnson](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/3ec8ea/32.png) [@benjohnson](https://www.ruby-forum.com/u/benjohnson)\
**Post date:** [September 1, 2008, 9:54pm UTC](https://www.ruby-forum.com/t/stripping-non-alphanumeric-characters/147441/2 "2008-09-01T21:54:04Z")

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Ben J. wrote:

> I know this is a noob question. What would be the best / most efficient  
> way to replace all non alphanumeric characters in a string?
> 
> Thanks for your help.

you didn’t say what you want to replace them _with_. Here I assumed you  
want to remove them. But you could use anything instead of just ‘’ in  
the 2nd argument to gsub.

ruby$ irb  
irb(main):001:0\> x = “ab\*&12%^cd”  
=\> “ab\*&12%^cd”  
irb(main):002:0\> x.gsub(/[^[:alnum:]]/, ‘’)  
=\> “ab12cd”

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<div class="post-metadata">

**Author:** ![benjohnson](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/3ec8ea/32.png) [@benjohnson](https://www.ruby-forum.com/u/benjohnson)\
**Post date:** [September 1, 2008, 10:08pm UTC](https://www.ruby-forum.com/t/stripping-non-alphanumeric-characters/147441/3 "2008-09-01T22:08:46Z")

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You’re the man, thanks.