preg_replace challenge

[jcaudill]

I have the following code:

<?
$string = 'SUV';
$patterns[0] = '/SUV/';
$patterns[1] = '/SUV/';
$replacements[0] = 'SUV (Sports Utility Vehicle)';
$replacements[1] = 'SUV (Sports Utility Motor Vehicle)';
echo preg_replace($patterns,$replacements,$string,1);
?>

The result is: SUV (Sports Utility Motor Vehicle) (Sports Utility Vehicle)

What I am trying to avoid is when I searched for the second SUV, it was only found ONCE in the original string. I don't want the second replacement to occur. This is the result I was hoping for:

SUV (Sports Utility Vehicle)

So say my original string contains SUV 50 times, I want those SUV matches to be replaced with one of 50 replacement pattern. I don't want it to replace already replaced words and count those as one of the 50. I want the replace to occur linearlly if you will. Make sense?

TIA

[jcaudill]

Bump...

Really need some help on this one 🙂 Linear replace if you will.

[Drakla]

Why are you replacing on the same thing twice - that's what doesn't make any sense.

[jcaudill]

I have a word I want to find, in this case SUV. But then I have one of several different replacements I can use, randomly. So, lets say I have a string with SUV occuring 15 times. I build a find array that will have a regex pattern in it, something like \bSUV\b/i 15 times. And then I'll have a replacement array, that will have random replacements, but when all is said and done it'll be 15 to match the 15 from the find array. So this should give me all I need to replace all occurences in a string. But it appears the way preg_replace works it's not smart enough to know you are only replacing on the original string.

[xblue]

Hi,

maybe preg_replace_callback() can help you with this task. Just to recap: do you want
- the replacement items to be inserted one after the other (as ordered in the array),
- or in random order
- or actually randomly (i.e. some items may show up more than ones while others do not show up at all)?
With V1 and 2 my 2nd question would be what should happen if there are more matches than # of elements in the replacement array?

If your pattern is as simple as in your first post, explode() and then concatening the elements of both arrays in the desired order would be an alternative.

[jcaudill]

Hi xblue:

Yes, the replacement array will already be randomized the way I want it. The find array will contain the exact number of matches in the string I'm doing the replace on because I'll have already used preg_match_all to get the number of matching elements. So, the two arrays are built exactly like I want them, I just want to now replace in order and not go over my work 🙂

THANKS!

[xblue]

If you are staying with regex, there is a thread that deals with a problem that is quite similar:
http://www.phpbuilder.com/board/showthread.php?s=&threadid=10297899
should be too difficult to modify it using a numeric array instead of numbers, I think. Let me know if you get stuck, I'll try to give you a hand.

[jcaudill]

Man I'm so close I can taste it, thanks to your help!

What I decided to do was use your $counter variable as an array key so I can pick the next value in my already available replacement array. I think this is going to work great but I'm stumped a bit. This is contained in a method in a class (PHP 4). For some reason when I try to use global to pass my replacement array into create_function it's not seeing it. So, there's something I'm missing I think, probably scope.

           $buffer = preg_replace_callback($word_pattern,
                     create_function('$matches',
                                     'global $replacement_array;
                                     static $counter = 0;
                                     $counter++;
                                     return $replacement_array[$counter-1];')
                     ,$buffer);

So $replacement_array is an array created within' my method within' my class.

I'll continue to search in the meantime!

[xblue]

Not sure if I can be of any more help. I tested this one, which seems to be very very close to yours except the way the array is created, and it worked fine, so I agree with you that this may be where the problem lies.

$replacements = array('SUV (Sports Utility Vehicle)', 'SUV (Sports Utility Motor Vehicle)', 'whatever');

$input = 'SUV text text text SUV text SUV';

$output = preg_replace_callback("/\bSUV\b/", create_function(
           '$matches',
           'global $replacements;
            static $counter = 0;
            $counter++;
            return $replacements[$counter-1];'
           ), $input);

echo $output;

[edit: wish the php tags would stop eating backslashes some day 🙁 ]

[jcaudill]

It turns out I just needed to use $GLOBALS and put my array in there before it could be available to create_function. I knew it had to be a scoping problem 🙂 I hate making things global.

Everything is working like a champ; and best of all it still seems to be just as fast and a bit less complex. So; thank you very much for all of your help xblue, I learned a bunch here!