php - iterate with preg_replace?

Question

I want to use preg_replace with one pattern and an array of replacements that are all different. In other words, for each occurrence of the match I want to iterate down the replacements array for a replacement.

Is there any way to do this?

I tried using preg_replace_callback - the callback accepts an array of matches but has to only return one string- no way to tell which match you are replacing.

I also tried using the count param and passing it the callback function - it's 0 every time and after the preg_replace is done it and thentells the total number of matches.

Steve Robbins · Accepted Answer · 2013-10-22 23:57:00Z

2

Taking @Andreas' answer and improving it a bit for performance:

$count = 1;
foreach ($replaceArray as $replace)
{
  preg_replace($pattern, $replace, $subject, 1, $count);

  if ($count == 0) 
    break;
}

This will check whether a replacement has been performed, and if that's not the case (as there's no more match), the loop is abandoned. This will save performance in case there are more elements in $replaceArray than matches in $subject.

edited Oct 22, 2013 at 23:57

Steve Robbins

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answered Oct 22, 2013 at 23:40

TheWolf

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1 Comment

inorganik Over a year ago

I didn't downvote, but actually, I don't need those extra lines of code because in my particular case there will always be the same number of items in the replacement array as what I'm replacing.

Steve Robbins · Accepted Answer · 2013-10-22 23:55:36Z

1

Try something along the lines:

foreach ($replaceArray as $replace)
{
    $subject = preg_replace($pattern, $replace, $subject, 1);
}

It will loop through you replacement array and replaces only 1 at a time.

edited Oct 22, 2013 at 23:55

Steve Robbins

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answered Oct 22, 2013 at 23:33

Andreas

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Comments

Casimir et Hippolyte · Accepted Answer · 2013-10-23 00:05:35Z

0

You don't need to iterate, if you create an array of patterns with the same size as your array of replacements, example:

$string = 'obo oto oko';
$pattern = '~o.o~i';
$replacements = array('glip', 'glap', 'glop');

$patterns = array_fill(0, count($replacements), $pattern);

$result = preg_replace($patterns, $replacements, $string, 1);
print_r($result);

answered Oct 23, 2013 at 0:05

Casimir et Hippolyte

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2 Comments

inorganik Over a year ago

I do need to iterate though, and I tried just that. Problem is I'm replacing the strings with strings that match the pattern. So for each item in the array, preg_replace goes back through the whole string and replaces the replacements.

Casimir et Hippolyte Over a year ago

@inorganik: Can you edit your post and write an example of input, patterns and desired output?

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