What is the difference between array_merge and array + array in PHP?

Both get the union of arrays, but array_merge() overwrites duplicate non_numeric keys. Let us now see an example of the array+array−

Example

 Live Demo

<?php
   $arr1 = array( "p"=>"150", "q"=>"100", "r"=>"120", "s"=>"110");
   $arr2 = array("t"=>"115", "u"=>"103", "v"=>"105", "w"=>"125" );
   var_dump ($arr1 + $arr2);
?>

Output

This will produce the following output−

array(8) {
   ["p"]=>
   string(3) "150"
   ["q"]=>
   string(3) "100"
   ["r"]=>
   string(3) "120"
   ["s"]=>
   string(3) "110"
   ["t"]=>
   string(3) "115"
   ["u"]=>
   string(3) "103"
   ["v"]=>
   string(3) "105"
   ["w"]=>
   string(3) "125"
}

Example

Let us now see an example of array_merge() in PHP−

 Live Demo

<?php
   $arr1 = array( "p"=>"150", "q"=>"100", "r"=>"120", "s"=>"110");
   $arr2 = array("t"=>"115", "u"=>"110", "v"=>"105", "w"=>"100" );
   var_dump (array_merge($arr1, $arr2));
?>

Output

This will produce the following output−

array(8) {
   ["p"]=>
   string(3) "150"
   ["q"]=>
   string(3) "100"
   ["r"]=>
   string(3) "120"
   ["s"]=>
   string(3) "110"
   ["t"]=>
   string(3) "115"
   ["u"]=>
   string(3) "110"
   ["v"]=>
   string(3) "105"
   ["w"]=>
   string(3) "100" 
}