Replace part of string between quotes in php regex

Question

Now I've got very basic regex skills, only used regex a couple of times for basic stuff. This has probably been asked before, which I apologize for, but I couldn't find any answer for this. Found similar, though and tried to adapt it but to no avail. OK, to the question - How do I replace a space only between certain characters (doublequotes in this case)?

Say i have the following string:

"mission podcast" modcast A B C "D E F"

I want to replace the spaces between mission and podcast as well as the ones between D, E & F whilst leaving the other ones untouched.

P.S. What if space was a string? An example for that is welcome as well.

Edited this a bit I hope now it's more clear. Edit 2: I need to do this on a string in php and execute it in the shell. Edit 3: I'm sorry i changed the whole question 3 times it's just i'm getting quite confused myself. Cheers!

Answer 1

Description

I would attack this problem by first splitting the string into groups of either quoted or not quoted strings.

Then iterating through the matches and if Capture Group 1 is populated, then that string is quoted so just do a simple replace on replace Capture Group 0. If Capture group 1 is not populated then skip to the next match.

On each iteration, you'd want to simply build up a new string.

Since splitting the string is the difficult part, I'd use this regex:

("[^"]*")|[^"]*

Example

Sample Text

"mission podcast" modcast A B C "D E F"

Code

PHP Code Example: 
<?php
$sourcestring="your source string";
preg_match_all('/("[^"]*")|[^"]*/i',$sourcestring,$matches);
echo "<pre>".print_r($matches,true);
?>

Capture Groups

$matches Array:
(
    [0] => Array
        (
            [0] => "mission podcast"
            [1] =>  modcast A B C 
            [2] => "D E F"
            [3] => 
        )

    [1] => Array
        (
            [0] => "mission podcast"
            [1] => 
            [2] => "D E F"
            [3] => 
        )

)

PHP Example

This php script will replace only the spaces inside quoted strings.

Working example: http://ideone.com/jBytL3

Code

<?php

$text ='"mission podcast" modcast A B C "D E F"';

preg_match_all('/("[^"]*")|[^"]*/',$text,$matches);

foreach($matches[0] as $entry){
    echo preg_replace('/\s(?=.*?")/ims','~~new~~',$entry);
    }

Output

"mission~~new~~podcast" modcast A B C "D~~new~~E~~new~~F"