3v4l.org

run code in 500+ PHP versions simultaneously
<?php $rest = substr("abcdef", 6, -2); $rest1 = substr("abcdef", 6, 4); var_dump($rest); var_dump($rest1);
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
string(0) "" string(0) ""
Output for 7.0.0 - 7.0.24, 7.1.0 - 7.1.20, 7.2.6 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33
bool(false) string(0) ""

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111.24 ms | 1461 KiB | 4 Q