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<?php $var = [ 'a' => 'a', 'b' => 'b', ]; array_walk($var, function ($value) { }); var_dump(key($var)); foreach ($var as $value) { } var_dump(key($var));
based on ihYBS
Output for 7.1.0 - 7.2.0
string(1) "a" string(1) "a"
Output for 5.4.11 - 7.0.20
NULL NULL
Output for 5.3.21 - 5.3.29
Parse error: syntax error, unexpected '[' in /in/nJF2k on line 3
Process exited with code 255.