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<?php $fileNow = "00123"; $counter = 0; while ($fileNow[0] == 0) { $fileNow = substr($fileNow, 1); var_dump('loop iteration: '.(++$counter).', value of $fileNow:', $fileNow); }
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.37, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
string(37) "loop iteration: 1, value of $fileNow:" string(4) "0123" string(37) "loop iteration: 2, value of $fileNow:" string(3) "123"

preferences:
229.63 ms | 406 KiB | 350 Q