PHP conditional string replacement str_replace

Question

This is the string i'm trying to replace white spaces between the words with "-".

$mystring = "Color red, Color blue, Color black";
$newstring = str_replace(' ', '-', $mystring);

What i want to achieve, using the str_replace function, is:

"Color-red, Color-blue, Color-black";

But that returns:

"Color-red,-Color-blue,-Color-black";

I guess i need a condition that replaces white spaces "not after the comma" or "between two words". But i have no idea. Any suggestion?

David B · Accepted Answer · 2012-06-08 00:03:52Z

4

(?<!,)\s

That uses a negative lookbehind to match all spaces (\s) that aren't followed by a ,.

preg_replace("/(?<!,)\s/", '-', $mystring);

answered Jun 8, 2012 at 0:03

David B

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