CODEWITHSUNDEEP
phpregexreplacepreg-replace
Glen
Glen

Reputation: 695

preg_replace() Only Specific Part Of String

I always have trouble with regex, I basically have a url, for example:

http://somedomain.com/something_here/bla/bla/bla/bla.jpg

What I need is a preg_replace() to replace the something_here with an empty string, and leave everything else in tact.

I have tried the following and it replaces the wrong parts:

$image[0] = preg_replace('/http:\/\/(.*)\/(.*)\/wp-content\/uploads\/(.*)/','$2' . '',$image[0]);

This ends up leaving only the part I want to replace, rather than actually replacing it!

Upvotes: 8

Views: 13364

Answers (4)

Maxim Mandrik
Maxim Mandrik

Reputation: 447

Unreliable usage:

In preg_replace('/(:\/\/.*?\/).*?\/()/', '$1$2', $string): if instead of empty string you need to put value from a variable that you do not control, then you need to escape the $ and \number characters, and this is quite a difficult task.

Reliable usage:

For difficult regular expressions where you need to replace part of a string, it can be very useful to do so (and most importantly, you don't need to escape $newValue for the characters $ and \number):

$newValue = '';

$newString = preg_replace_callback(
  '/(:\/\/.*?\/).*?\/()/',
  function($match) use ($newValue) { return $match[1].$newValue.$match[2]; },
  $string
);

Upvotes: 0

PleaseStand
PleaseStand

Reputation: 32052

You could do this:

$image[0] = preg_replace('!^(http://[^/]*)/[^/]*!', '$1', $image[0]);

Or you might consider just splitting the string to work on its individual components:

$parts = explode('/', $image[0]);
unset($parts[3]);
$image[0] = implode('/', $parts);

Upvotes: 2

HamZa
HamZa

Reputation: 14921

The following code is based on the description you provided:

$url = 'http://somedomain.com/something_here/bla/bla/bla/bla.jpg';
$output = preg_replace('#^(https?://[^/]+/)[^/]+/(.*)$#', '$1$2', $url);
echo $output; // http://somedomain.com/bla/bla/bla/bla.jpg

Explanation:

  • ^ : match begin of line
  • ( : start matching group 1
    • https?:// : match http or https protocol
    • [^/]+ : match anything except / one or more times
    • / : match /
  • ) : end matching group 1
  • [^/]+ : match anything except / one or more times -/ : match /
  • ( : start matching group 2
    • .* : match anything zero or more times (greedy)
  • ) : end matching group 2
  • $ : match end of line

Upvotes: 8

cmbuckley
cmbuckley

Reputation: 42458

You could do this with a simple string replace:

$image[0] = str_replace('/wp-content/uploads/', '/', $image[0]);

Or if you want to use a regular expression:

$image[0] = preg_replace('~(http://.*?)/wp-content/uploads/(.*)~', '$1/$2', $image[0]);

Upvotes: 1

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