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<?php $a = array(1 => 1, 'c'=>2, 'b'=>3, 'd'=>4); $a[] = "first value with implicit key"; unset($a['c']); $a['a'] = "new a"; $a[] = "second value with implicit key"; $a['b'] = "replaced b"; var_export($a);
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, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.30, 7.0.0 - 7.0.29, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.30, 8.0.0 - 8.0.22, 8.1.0 - 8.1.9
array ( 1 => 1, 'b' => 'replaced b', 'd' => 4, 2 => 'first value with implicit key', 'a' => 'new a', 3 => 'second value with implicit key', )

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