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run code in 300+ PHP versions simultaneously
<?php $a = array( 'a'=>1, 'b'=>2, 'c'=>3 ); $b = array( 'b'=>3, 'c'=>4, 'd'=>5 ); echo $a + $b; foreach(array_keys($a + $b) as $key){ echo $key; }
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Warning: Array to string conversion in /in/Y0oTe on line 12 Arrayabcd
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 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 - 7.3.31, 7.4.0 - 7.4.25, 7.4.27 - 7.4.33
Notice: Array to string conversion in /in/Y0oTe on line 12 Arrayabcd
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, 7.3.32 - 7.3.33, 7.4.26
Arrayabcd

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237.8 ms | 403 KiB | 356 Q