How do I strip non alphanumeric characters from a string and keep spaces?

Question

I want to create a regex that removes all non-alphanumber characters but keeps spaces. This is to clean search input before it hits the db. Here's what I have so far:

@search_query = @search_query.gsub(/[^0-9a-z]/i, '')

Problem here is it removes all the spaces. Solutions on how to retain spaces?

I don't do Rails development, but why can't you let Rails do the sanitization? — Andrew Grimm, May 24 '11 at 23:04

score 206 · Accepted Answer · answered May 23 '11 at 23:37

206

Add spaces to the negated character group:

@search_query = @search_query.gsub(/[^0-9a-z ]/i, '')

answered May 23 '11 at 23:37

jwueller

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The empty space didn't work for me, so '\s' may also be an option: @search_query.gsub(/[^0-9a-z\\s]/i, '') – David Douglas Dec 06 '13 at 12:09
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slightly less wordy: `@search_query.gsub!(/[^0-9a-z ]/i, '')` – Benjineer Jul 20 '14 at 09:49
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Just to precise, this remove all accented letters and may not be adapted to some languages. – Uelb Nov 25 '15 at 16:25
@DavidDouglas That should be `\s` not `\\s` – Dex Jan 03 '16 at 09:15

score 14 · Answer 2 · answered Aug 12 '14 at 09:17

14

In this case I would use the bang method (gsub! instead of gsub) in order to clean the input permanently.

#permanently filter all non-alphanumeric characters, except _
@search_query.gsub!(/\W/,'')

This avoids a situation where @seach_query is used elsewhere in the code without cleaning it.

answered Aug 12 '14 at 09:17

nvugteveen

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The bang version will return nil if nothing was matched. Probably not the result you'd want or expect. From the docs _"Performs the substitutions of String#gsub in place, returning str, or nil if no substitutions were performed. If no block and no replacement is given, an enumerator is returned instead."_ – dft Jan 20 '16 at 06:45
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In his example the return value isn't used, so that's pretty much irrelevant. – Jaap Haagmans Mar 22 '17 at 08:36

score 3 · Answer 3 · edited Jul 07 '17 at 15:55

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I would have used the inclusion approach. Rather than exclude all but numbers, I would only included numbers. E.g.

@search_query.scan(/[\da-z\s]/i).join

edited Jul 07 '17 at 15:55

Travis

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answered Dec 31 '14 at 23:39

Vadym Tyemirov

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score 0 · Answer 4 · answered Apr 12 '19 at 10:15

0

Maybe this will work for such case:

# do not replace any word characters and spaces
@search_query = @search_query.gsub(/[^\w ]/g, '')

answered Apr 12 '19 at 10:15

piton4eg

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score -3 · Answer 5 · answered May 04 '14 at 17:52

-3

A better answer (at least in ruby) is:

@search_query.gsub!(/^(\w|\s*)/,'')

answered May 04 '14 at 17:52

John Doe

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This is going to remove either (a) a single word character or (b) any number of whitespace from the beginning of the string. Completely unrelated to the question, and therefore not an answer. – Sigi May 04 '14 at 19:48
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made a big mistake .. don't know what i was thinking :=( – John Doe May 10 '14 at 19:03

How do I strip non alphanumeric characters from a string and keep spaces?

5 Answers5