Regular Expression for replacing string

Question

How can I write regular expression to remove double dash -- into single dash - and if string start or end with dash replace with empty string.

var oldString = "abc--xyz--"
var filtered = oldStringt.replace(???????);

Sample Input >>>> Output

abc--xyz--       >>>>>    abc-xyz
abc---xyz-123    >>>>>    abc-xyz-123
--abc-xyz-123    >>>>>    abc-xyz-123

Roland Mai · Accepted Answer · 2012-11-13 20:43:20Z

6

How about chaining replaces:

str.replace(/[-]+/g, '-').replace(/[-]+$/g, '').replace(/^[-]+/g, '')

answered Nov 13, 2012 at 20:43

Roland Mai

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2 Comments

Upvote! No need for the square brackets, though (at least not in my console JS interpreter).

Why compile and execute 3 regexp’s when only one is needed?

user1726343 · Accepted Answer · 2012-11-13 20:42:13Z

2

oldString.replace(/-+/g,"-").replace(/(^-+)|(-+$)/g,"");

answered Nov 13, 2012 at 20:42

user1726343

David Hellsing · Accepted Answer · 2012-11-13 21:11:42Z

0

Here is a single regexp that should work:

oldString.replace(/^-+|-+$|(-)+/g, '$1')

Now, I know you specifically asked for regexp, but many replaces like this one can be done using arrays as well (and sometimes they are faster):

oldString.split(/-+/).filter(function(e){return !!e}).join('-')

answered Nov 13, 2012 at 21:06

David Hellsing

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