Array Merging In PHP: Simple, Associative, And Multidimensional Arrays

In Php

Merging arrays is a common operation in PHP when you need to combine the elements of two or more arrays into a single array. This can be useful in various scenarios, such as when you want to combine data from different sources, create a new array with unique values, or simply restructure your data. In this blog post, we'll explore how to merge arrays in PHP, including simple arrays, associative arrays, and multidimensional arrays, with examples for each case.

Merging Simple Arrays


Method 1: Using the array_merge() Function

The array_merge() function is a straightforward way to merge two or more simple arrays. It appends the elements of the second array to the first array, and so on for any additional arrays provided as arguments. Here's how you can use it:

$array1 = [1, 2, 3];
$array2 = [4, 5, 6];
$mergedArray = array_merge($array1, $array2);
print_r($mergedArray);

In this example, $mergedArray will contain [1, 2, 3, 4, 5, 6].


Method 2: Using the + Operator

You can also merge simple arrays using the + operator. This method combines the arrays and retains unique elements from both arrays. If there are duplicate values, the elements from the first array will be preserved.

$array1 = [1, 2, 3];
$array2 = [3, 4, 5];
$mergedArray = $array1 + $array2;
print_r($mergedArray);

The resulting $mergedArray will be [1, 2, 3], and the element 3 from the second array is ignored.

Merging Associative Arrays

Merging associative arrays is similar to merging simple arrays, but you need to be careful about how keys are handled. Here's how you can merge associative arrays:

$array1 = ['a' => 1, 'b' => 2, 'c' => 3];
$array2 = ['b' => 4, 'd' => 5];
$mergedArray = $array1 + $array2;
print_r($mergedArray);

In this case, the resulting $mergedArray will be ['a' => 1, 'b' => 2, 'c' => 3, 'd' => 5]. The key 'b' from the second array overwrites the value in the first array.


If you want to merge associative arrays while preserving all values, you can use a combination of the array_merge() function and the + operator:

$mergedArray = array_merge($array1, $array2);
$mergedArray += $array1;
$mergedArray += $array2;
print_r($mergedArray);

Merging Multidimensional Arrays

Merging multidimensional arrays can be more complex, but it's certainly achievable. You can use the methods described above for merging simple and associative arrays, but you'll need to iterate through the nested arrays if you want to merge multidimensional arrays element by element.


Here's an example of how to merge two multidimensional arrays:

$array1 = [
    ['a' => 1, 'b' => 2],
    ['c' => 3, 'd' => 4],
];

$array2 = [
    ['b' => 5, 'e' => 6],
    ['f' => 7, 'g' => 8],
];

$mergedArray = [];
foreach ($array1 as $key => $value) {
    $mergedArray[] = $value + $array2[$key];
}

print_r($mergedArray);


The resulting $mergedArray will contain:

Array
(
    [0] => Array
        (
            [a] => 1
            [b] => 5
            [e] => 6
        )

    [1] => Array
        (
            [c] => 3
            [d] => 4
            [f] => 7
            [g] => 8
        )
)


In this example, we iterated through each element of the arrays and merged them into a new multidimensional array.


Merging arrays is a fundamental operation in PHP, and these methods allow you to combine arrays of different types and structures. Whether you're working with simple arrays, associative arrays, or multidimensional arrays, PHP provides the tools you need to merge them effectively.

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