Ask PHP to use a regular expression string, just want to keep the first what to do

Does PHP use regular expression strings, just want to keep the first one to do?
Php
For example, there are many ASD for this string, there are several consecutive, there are just one,

But I want to keep only the first ASD, and all the ASD in the back are erased.

(on the basis of not affecting other characters)


Ssssssssgsdfasdasdasdasdjlkjhkjhalkasdasdjsdkajshdasdaklsjdasdhkjashgdaklsh

Desired Result:



Ssssssssgsdfasdjlkjhkjhalkjsdkajshdaklsjdhkjashgdaklsh

Ask the master to give some hints

Share to:

------Solution--------------------

$s = ' ssssssssgsdfasdasdasdasdjlkjhkjhalkasdasdjsdkajshdasdaklsjdasdhkjashgdaklsh ';
$t = ' Ssssssssgsdfasdjlkjhkjhalkjsdkajshdaklsjdhkjashgdaklsh ';
$s = preg_replace_callback ('/asd/', function ($r) {
  static $n = 0;
  Return! $n + +? $r [0]: ";
  }, $s);

BOOL (TRUE)

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