Question

I’ve been struggling to find a way to replace spaces with dashes in a string but only spaces that are within a particular part of the string.

Source:

ABC *This is a sub string* DEF

My attempt at a regular expression:

/\s/g

If I use the regular expression to match spaces and replace I get the following result:

ABC-*This-is-a-sub-string*-DEF

But I only want to replace spaces within the text surrounded by the two asterisks.

Here is what I’m trying to achieve:

ABC *This-is-a-sub-string* DEF

Not sure why type of regular expressions I’m using as I’m using the find and replace in TextMate with Regular Expressions option enabled.

It’s important to note that the strings that I will be running this regular expression search and replace on will have different text but it’s just the spaces within the asterisks that I want to match.

Any help will be appreciated.

Answer 1

To identify spaces that are surrounded by asterisks, the key observation is, that, if asterisks appear only in pairs, the spaces you look for are always followed by an odd number of asterisks.

The regex

\ (?=[^*]*\*([^*]*\*[^*]*\*)*[^*]*$)

will match the once that should be replaced. Textmate would have to support look-ahead assertions for this to work.