//array union or merge $a = array('One', 'Two'); $b = array('Three', 'Four'); print '
'; print_r($a + $b); print '
'; //array union and assign $b += array('Five', 'Six'); print '
'; print_r($b); print '
'; //array equal var_dump($a == $b); echo '
'; //array not equal var_dump($a != $b); echo '
'; var_dump($a <> $b); echo '
'; //identical var_dump($a === $a); echo '
'; var_dump($a === $b); echo '
'; //not identical var_dump($a !== $a); echo '
'; var_dump($a !== $b);
Hello World!