3v4l.org

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<?php $in = "1234"; $arr = array($in => "foobar"); $keys = array_keys($arr); $out = $keys[0]; var_dump($key); var_dump($in == $out); var_dump($in === $out); ?>
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 variable $key in /in/lkCmV on line 7 NULL bool(true) bool(false)
Output for 5.0.4 - 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 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.25, 7.4.27 - 7.4.33
Notice: Undefined variable: key in /in/lkCmV on line 7 NULL bool(true) bool(false)
Output for 7.3.32 - 7.3.33, 7.4.26
NULL bool(true) bool(false)
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.3
Notice: Undefined variable: key in /in/lkCmV on line 7 NULL bool(true) bool(false)

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283.53 ms | 402 KiB | 456 Q