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  1. <?php
  2. $string = "I want to replace ' with \' but not \' since they are already escaped";
  3. $regex = "~(?<!\\\)'~";
  4.  
  5. echo preg_replace($regex, "\\'", $string);
  6.  
Success #stdin #stdout 0.02s 52472KB
comments (?)
stdin 
Standard input is empty
stdout 
I want to replace \' with \' but not \' since they are already escaped
https://ideone.com/Un3rNM
language:
PHP (php 7.3.5)
created:
8 years ago
visibility:
public

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