Merge one or more arrays

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- PHP Manual
- Array Functions
- Merge one or more arrays

# array_merge

(PHP 4, PHP 5, PHP 7, PHP 8)

array_merge — Merge one or more arrays

### Description

array_merge(array `...$arrays`): array

Merges the elements of one or more arrays together so that the values of one are appended to the end of the previous one. It returns the resulting array.

If the input arrays have the same string keys, then the later value for that key will overwrite the previous one. If, however, the arrays contain numeric keys, the later value will not overwrite the original value, but will be appended.

Values in the input arrays with numeric keys will be renumbered with incrementing keys starting from zero in the result array.

### Parameters

`arrays`

  Variable list of arrays to merge.

### Return Values

Returns the resulting array. If called without any arguments, returns an empty array.

### Changelog

Version | Description
--- | ---
7.4.0 | This function can now be called without any parameter. Formerly, at least one parameter has been required.

### Examples

Example #1 array_merge() example

    <?php
    $array1 = array("color" => "red", 2, 4);
    $array2 = array("a", "b", "color" => "green", "shape" => "trapezoid", 4);
    $result = array_merge($array1, $array2);
    print_r($result);
    ?>

The above example will output:

    Array
    (
        [color] => green
        [0] => 2
        [1] => 4
        [2] => a
        [3] => b
        [shape] => trapezoid
        [4] => 4
    )

Example #2 Simple array_merge() example

    <?php
    $array1 = array();
    $array2 = array(1 => "data");
    $result = array_merge($array1, $array2);
    ?>

Don't forget that numeric keys will be renumbered!

    Array
    (
        [0] => data
    )

If you want to append array elements from the second array to the first array while not overwriting the elements from the first array and not re-indexing, use the `+` array union operator:

    <?php
    $array1 = array(0 => 'zero_a', 2 => 'two_a', 3 => 'three_a');
    $array2 = array(1 => 'one_b', 3 => 'three_b', 4 => 'four_b');
    $result = $array1 + $array2;
    var_dump($result);
    ?>

The keys from the first array will be preserved. If an array key exists in both arrays, then the element from the first array will be used and the matching key's element from the second array will be ignored.

    array(5) {
      [0]=>
      string(6) "zero_a"
      [2]=>
      string(5) "two_a"
      [3]=>
      string(7) "three_a"
      [1]=>
      string(5) "one_b"
      [4]=>
      string(6) "four_b"
    }

Example #3 array_merge() with non-array types

    <?php
    $beginning = 'foo';
    $end = array(1 => 'bar');
    $result = array_merge((array) $beginning, (array) $end);
    print_r($result);
    ?>

The above example will output:

    Array
        (
            [0] => foo
            [1] => bar
        )

### See Also

- array_merge_recursive() - Merge one or more arrays recursively
- array_replace() - Replaces elements from passed arrays into the first array
- array_combine() - Creates an array by using one array for keys and another for its values
- array operators