I have this code :
$count = 0;
preg_replace('/test/', 'test'. $count, $content,-1,$count);
For every replace, I obtain test0.
I would like to get test0, test1, test2 etc..
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Relevant reading: Replacement a string one-at-a-time using incremented replacement stringsmickmackusa– mickmackusa ♦2024-08-16 20:33:00 +00:00Commented Aug 16, 2024 at 20:33
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6 Answers
$count = 0;
preg_replace_callback('/test/', 'rep_count', $content);
function rep_count($matches) {
global $count;
return 'test' . $count++;
}
Comments
class TestReplace {
protected $_count = 0;
public function replace($pattern, $text) {
$this->_count = 0;
return preg_replace_callback($pattern, array($this, '_callback'), $text);
}
public function _callback($matches) {
return 'test' . $this->_count++;
}
}
$replacer = new TestReplace();
$replacer->replace('/test/', 'test test test'); // 'test0 test1 test2'
Note: Using global is the hard-and-fast solution but it introduces some problems, so I don't recommend it.
2 Comments
cletus
Global has no more problems than the overcomplicated object solution. People get stuck on globals in PHP because of the C/C++/etc stigmatism, which is misplaced. Globals in PHP are simply request-scoped variables. Less hand-wringing, more pragmatism.
Aberel
A CLASS here is not needed and may confuse the answer for this question. You just may give a clean example of using "preg_replace_callback"
Following the release of PHP5.3 we can now use a closure and the use keyword to get around the global issue raised by Emil above:
$text = "item1,\nitem2,\nFINDME:23623,\nfoo1,\nfoo2,\nfoo3,\nFINDME:923653245,\nbar1,\nbar2,\nFINDME:43572342,\nbar3,\nbar4";
$pattern = '/FINDME:(\d+)/';
$count = 1;
$text = preg_replace_callback( $pattern
, function($match) use (&$count) {
$str = "Found match $count: {$match[1]}!";
$count++;
return $str;
}
, $text
);
echo "<pre>$text</pre>";
Which returns:
item1,
item2,
Found match 1: 23623!,
foo1,
foo2,
foo3,
Found match 2: 923653245!,
bar1,
bar2,
Found match 3: 43572342!,
bar3,
bar4
Note the use (&$count) following the function name - this allows us to read $count in the scope of the function (the & making it passed by reference and therefore writeable from the scope of the function).
Comments
Also, if you want to avoid using global:
$count = 0;
preg_replace_callback('/test/', function rep_count($matches) use (&$count) {
return 'test' . $count++;
}, $content);
Comments
You only have to define a static variable in the callback function:
$result = preg_replace_callback('/test/', function ($m) {
static $count = 0;
return 'test' . $count++;
}, $content);
This way you don't pollute the global namespace.
For this specific case you can also use simple functions:
$parts = explode('test', $content);
$end = array_pop($parts);
$result = '';
foreach($parts as $k=>$v) {
$result .= 'test' . $k;
}
$result .= $end;
answered Jul 28, 2017 at 13:49
Casimir et Hippolyte
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Comments
preg_replace_callback() will allow you to operate upon the match before returning it for subsequent replacement.
answered Feb 2, 2010 at 14:17
Ignacio Vazquez-Abrams
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