3v4l.org

run code in 300+ PHP versions simultaneously
<?php $hello[0]["1"] = "v:a"; $hello[0]["2"] = "v:b"; for($i=0;$i<count($hello[0]);$i++) { echo $hello[0]["a".$i+1]; }
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
Warning: Undefined array key "a1" in /in/jDCCJ on line 9 Warning: Undefined array key "a2" in /in/jDCCJ on line 9
Output for 7.4.0 - 7.4.33
Deprecated: The behavior of unparenthesized expressions containing both '.' and '+'/'-' will change in PHP 8: '+'/'-' will take a higher precedence in /in/jDCCJ on line 9 Warning: A non-numeric value encountered in /in/jDCCJ on line 9 v:a Warning: A non-numeric value encountered in /in/jDCCJ on line 9 v:a
Output for 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33
Warning: A non-numeric value encountered in /in/jDCCJ on line 9 v:a Warning: A non-numeric value encountered in /in/jDCCJ on line 9 v:a
Output for 7.0.0 - 7.0.20
v:av:a

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143.02 ms | 401 KiB | 169 Q