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  1. <?php
  2.  
  3. $input_lines = '\\1s \\\\2s \\\\\\3s';
  4. echo $input_lines . "\n";
  5. echo preg_replace("/\\\\{2,}/", "\\\\", $input_lines);
  6. echo "\n".preg_replace('/\\\\{2,}/', '\\\\', $input_lines);
Success #stdin #stdout 0.03s 52472KB
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stdin
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Standard input is empty
stdout
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\1s \\2s \\\3s
\1s \2s \3s
\1s \2s \3s
https://ideone.com/yrCq5Y
language:
PHP (php 7.3.5)
created:
9 years ago
visibility:
secret

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