How to replace underscores with spaces using a regex in Javascript

Question

How can I replace underscores with spaces using a regex in Javascript?

var ZZZ = "This_is_my_name";

Any hint on programming language? Regex doesn't replace anything by itself. `string.replace(/_/, " ")` — Marcel Jackwerth, Mar 18 '11 at 18:17
Which language (looks like JavaScript)? This can be done without regex (but not in JavaScript ;)) In VIM: `:%s/_/ /g` — Felix Kling, Mar 18 '11 at 18:17
Regular expressions can’t replace anything. They can only describe some grammar. But many language use regular expressions to search for certain strings. So what language do you use? — Gumbo, Mar 18 '11 at 18:18
How can I replace underscores with spaces using a regex in Javascript? — Karim Ali, Mar 18 '11 at 18:23

score 61 · Accepted Answer · answered Mar 18 '11 at 18:23

61

If it is a JavaScript code, write this, to have transformed string in ZZZ2:

var ZZZ = "This_is_my_name";
var ZZZ2 = ZZZ.replace(/_/g, " ");

also, you can do it in less efficient, but more funky, way, without using regex:

var ZZZ = "This_is_my_name";
var ZZZ2 = ZZZ.split("_").join(" ");

answered Mar 18 '11 at 18:23

pepkin88

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To quote [Crescent Fresh](http://stackoverflow.com/a/441035/1778898) quoting [John Resig](http://ejohn.org/blog/javascript-micro-templating/), it is actually more efficient currently doing the latter approach of .split("_").join(" "). – Justin Sep 10 '14 at 06:53
I agree. I believe the first method will only replace the first underscore in the string – Adam Joseph Looze Mar 06 '15 at 03:46
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@AdamJosephLooze Did you check it? The `g` flag takes care of replacing all occurrences. – pepkin88 Mar 06 '15 at 15:52
ya. i had a list of cities, and it only changed the underscore in the first instance. so i used split join and it worked for me. but i see everybody else is using the same replace, so it must work properly, but it did not for me. i ran mine in a for loop to print out all cities and it only worked with first instance. – Adam Joseph Looze Mar 06 '15 at 19:12
@AdamJosephLooze Both of my snippets are compliant with ES3, ES5 (and higher) specs. If you had a problem with the replace method **with a regular expression with a `g` flag** (that flag is important), that may be because of a faulty JS engine implementation or because of a mistake in the code. Could you show me your code, maybe I could help? (maybe with http://jsbin.com/) – pepkin88 Mar 07 '15 at 15:24

Jack · Answer 2 · 2011-03-18T18:25:31.217

Regular expressions are not a tool to replace texts inside strings but just something that can search for patterns inside strings. You need to provide a context of a programming language to have your solution.

I can tell you that the regex _ will match the underscore but nothing more.

For example in Groovy you would do something like:

"This_is_my_name".replaceAll(/_/," ")
    ===> This is my name

but this is just language specific (replaceAll method)..

score 0 · Answer 3 · answered Aug 15 '12 at 13:48

0

var str1="my__st_ri_ng";
var str2=str1.replace(/_/g, ' ');

answered Aug 15 '12 at 13:48

Aamir Afridi

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score 0 · Answer 4 · answered Mar 18 '11 at 18:17

0

Replace "_" with " "

The actual implementation depends on your language.

In Perl it would be:

s/_/ /g

But the truth is, if you are replacing a fixed string with something else, you don't need a regular expression, you can use your language/library's basic string replacement algorithms.

Another possible Perl solution would be:

tr/_/ /

answered Mar 18 '11 at 18:17

Adam Batkin

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You are right. Except the question didn't say anything about JavaScript when I wrote this answer. – Adam Batkin Jul 19 '16 at 21:35

How to replace underscores with spaces using a regex in Javascript

4 Answers4