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Is there any difference

1 years ago Views 125 Visit Post Reply

Is there any difference between  array_merge and array + array. Both return the same thing.

$merge = array_merge($arrayCar, $arrayBike);

and

$merged = $arrayCar+ $arrayBike;


Thread Reply

Bili Greed

- 1 years ago

The difference is:

The + operator takes the union of the two arrays, whereas the array_merge function takes the union BUT the duplicate keys are overwritten).
???????

here's a simple illustrative test:

$ar1 = [
   0  => '1-0',
  'a' => '1-a',
  'b' => '1-b'
];


$ar2 = [
   0  => '2-0',
   1  => '2-1',
  'b' => '2-b',
  'c' => '2-c'
];

print_r($ar1+$ar2);

print_r(array_merge($ar1,$ar2));

with the result:

Array
(
  [0] => 1-0
  [a] => 1-a
  [b] => 1-b
  [1] => 2-1
  [c] => 2-c
)
Array
(
  [0] => 1-0
  [a] => 1-a
  [b] => 2-b
  [1] => 2-0
  [2] => 2-1
  [c] => 2-c
)