Javascript, regex: Replace specified characters with space and matched character

Question

I am trying to use javascript replace() with a regex expression so that when it matches certain characters like: .,!? it will replace the matched character with itself surrounded by spaces. For example the string "hello?!?" will become "hello ? ! ? ".

Is there a better way than just doing a string.replace() for each character I wish replace?

I know I can select on the characters easy enough with '/[!\?\.]/g', but getting it to replace it with the same character it matched with is eluding me.

Should there be one or two spaces between ? and ! in your example? — t.niese
– t.niese, Commented Jul 10, 2013 at 19:32
Either way, after I split the sentence using / +/g which accounts for any number of spaces being between them to account for user error — Scott101
– Scott101, Commented Jul 10, 2013 at 19:35
If the number of spaces does not matter then the answer of LeonardChallis is the one you are looking for. — t.niese
– t.niese, Commented Jul 10, 2013 at 19:37

Tracker1 · Accepted Answer · 2013-07-10 19:34:15Z

5

It's as simple as adding a back-reference, like so:

"hello?!?".replace(/([!?\,\.])/g, ' $1 ');

edited Jul 10, 2013 at 19:34

Tracker1

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answered Jul 10, 2013 at 19:30

LeonardChallis

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5 Comments

Scott101 Over a year ago

Is there any sort of escape for the back reference? Doing the above gives me "hello $1 $1 $1".

go-oleg Over a year ago

This will add two spaces between consecutive special characters.

Tracker1 Over a year ago

@Scott101 I edited to escape the period in the regex, as well as add the comma in your request above. If you copy/paste the line above and run it in the js console in your browser, it works as requested.

Scott101 Over a year ago

@go-oleg That is ok for what I am doing as I immediately split the string using / +/g. The string is user input that I need to break up and I don't trust them to not put in multiple spaces between words.

Scott101 Over a year ago

@Tracker1 Awesome thanks, forgot to surround the regex in the parentheses. I'll have to wait to accept the answer in 3 min as stack overflow won't let me accept it yet.

Evan Knowles · Accepted Answer · 2013-07-10 19:29:22Z

0

If '/[!\?.]/g' matches as a regex, just capture the group by surrounding it with ()'s '/([!\?.])/g'

Then use the returned matched group to get the character you matched

answered Jul 10, 2013 at 19:29

Evan Knowles

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