The difference between PHP array addition and array_merge

The powerful functions of PHP array processing lead to various data processing functions.

Among them, array addition and array_merge caused the author to step into a small pit.

1

        public function action_test54(){
                $a = array(
                        '0'=>1567,
                        '1'=>1568,
                        '2'=>1569,
                        '3'=>1570,
                );
                $b = array(
                        '1'=>1571,
                        '2'=>1572,
                        '3'=>1573,
                        '4'=>1574
                );
                d($a + $b);
                dd(array_merge($a,$b));

        }

Demo2 output:

<small>array</small>(5) (
    0 => <small>integer</small> 1567
    1 => <small>integer</small> 1568
    2 => <small>integer</small> 1569
    3 => <small>integer</small> 1570
    4 => <small>integer</small> 1574
)

<small>array</small>(8) (
    0 => <small>integer</small> 1567
    1 => <small>integer</small> 1568
    2 => <small>integer</small> 1569
    3 => <small>integer</small> 1570
    4 => <small>integer</small> 1571
    5 => <small>integer</small> 1572
    6 => <small>integer</small> 1573
    7 => <small>integer</small> 1574
)

Conclusion:

$a + $b incremental coverage

array_merger($a,$b) $b replaces $a first

The above has introduced the difference between PHP array addition and array_merge, including the relevant aspects. I hope it will be helpful to friends who are interested in PHP tutorials.