Regex to remove all non alpha-numeric and replace spaces with +

Question

I'm looking to use regex to try remove all non alpha-numeric characters from a string and replace spaces with a +

All I want to permit is basically alphabetical words A-Z and +

This is specifically to prepare the string to become a part of a URL, thus need the + symbols instead of spaces.

I have looked at /\W+/ however this removes all white spaces and alpha-numeric characters, whereas I want to leave the spaces in if possible to then be replaced by + symbols.

I've searched around a bit but I can't seem to find something, I was hoping someone might have any simple suggestions for this.

Sample string & Desired result: Durarara!!x2 Ten -> durarara+x2+ten

Paul Roub · Accepted Answer · 2016-06-20 20:24:29Z

47

This is actually fairly straightforward.

Assuming str is the string you're cleaning up:

str = str.replace(/[^a-z0-9+]+/gi, '+');

The ^ means "anything not in this list of characters". The + after the [...] group means "one or more". /gi means "replace all of these that you find, without regard to case".

So any stretch of characters that are not letters, numbers, or '+' will be converted into a single '+'.

To remove parenthesized substrings (as requested in the comments), do this replacement first:

str = str.replace(/\(.+?\)/g, '');

function replacer() {

  var str = document.getElementById('before').value.
    replace(/\(.+?\)/g, '').
    replace(/[^a-z0-9+]+/gi, '+');

  document.getElementById('after').value = str;
}

document.getElementById('replacem').onclick = replacer;

<p>Before:
  <input id="before" value="Durarara!!x2 Ten" />
</p>

<p>
  <input type="button" value="replace" id="replacem" />
</p>

<p>After:
  <input id="after" value="" readonly />
</p>

edited Jun 20, 2016 at 20:24

answered Aug 19, 2015 at 21:54

Paul Roub

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4 Comments

sbhzi Over a year ago

Thanks! This is almost there, just one question, this replaces parenthesis with a plus symbol also, such as: Arslan Senki (TV) into Arslan+Senki++TV+, is there a way it can not add the + but instead remove "(TV)" altogether? I've never been that great with regex, I appreciate your help!

Paul Roub Over a year ago

Before the above replacement, add another line: str = str.replace(/\(.+?\)/g, '');

sbhzi Over a year ago

This is the best answer, I modified the second regex to be /\.|\(.+?\)/g to remove the periods/full-stops as well, should have mentioned it, my bad! Thanks a ton.

Norbert Over a year ago

I needed to add it to a regexp like so const myRex = new RegExp('[^a-z0-9+]+,'g') then do str.replaceAll(myRex,'')

Praveen reddy Dandu · Accepted Answer · 2015-08-19 22:30:55Z

2

 str = str.replace(/\s+/g, '+');
 str  = str.replace(/[^a-zA-Z0-9+]/g, "");

First line replaces all the spaces with + symbol
Second line removes all the non-alphanumeric and non '+' symbols.

edited Aug 19, 2015 at 22:30

answered Aug 19, 2015 at 22:01

Praveen reddy Dandu

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3 Comments

Paul Roub Over a year ago

That would remove all non-alphanumeric chars in the first line. Nothing left to replace with + in the second line.

Barett Over a year ago

It'd be Super Awesome if you could describe your approach in addition to the code you post. :)

sinisake Over a year ago

OP wants to replace every occurrence of space or non-alphanumeric symbol with JUST ONE '+' sign....durarara+x2+ten is desired result....

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