Using PHP array_merge() to Combine Arrays: Syntax, Examples, and Tips

PHP provides many powerful functions for handling arrays, and one of the most useful is array_merge(), which merges multiple arrays into a new array and returns the result.

The syntax of array_merge() is straightforward:

array_merge ( array $array1 [, array $... ] ) : array

The function accepts any number of array arguments and returns a single combined array.

Example 1: Merging Two Arrays

$array1 = array('apple', 'banana', 'orange');
$array2 = array('kiwi', 'melon', 'grape');
$result = array_merge($array1, $array2);
print_r($result);

Output:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
    [3] => kiwi
    [4] => melon
    [5] => grape
)

This demonstrates that the two original arrays are combined, preserving the order of elements.

Example 2: Merging Multiple Arrays

$array1 = array('apple', 'banana', 'orange');
$array2 = array('kiwi', 'melon', 'grape');
$array3 = array('strawberry', 'pineapple');
$result = array_merge($array1, $array2, $array3);
print_r($result);

Output:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
    [3] => kiwi
    [4] => melon
    [5] => grape
    [6] => strawberry
    [7] => pineapple
)

The function can handle any number of arrays, appending each subsequent array's elements to the result.

Example 3: Merging Associative Arrays

$array1 = array('name' => 'John', 'age' => 25);
$array2 = array('name' => 'Jane', 'email' => '[email protected]');
$result = array_merge($array1, $array2);
print_r($result);

Output:

Array
(
    [name] => Jane
    [age] => 25
    [email] => [email protected]
)

When merging associative arrays, duplicate keys are overwritten by the later array's values, as shown with the 'name' key.

Summary

The array_merge() function is a versatile tool for combining both indexed and associative arrays in PHP. It offers a concise and efficient way to merge data structures, making array manipulation more flexible in real‑world applications.