How to merge two arrays in PHP

How to merge two arrays in PHP

In PHP programming, you often encounter situations where you need to merge two arrays. PHP provides a variety of methods to implement array merging operations. This article will introduce several of the common methods, with code examples.

Method 1: Use array_merge function

The array_merge function is a built-in function provided by PHP for merging arrays. It accepts multiple arrays as parameters and returns a merged new array.

The following is a code example of using the array_merge function to merge two arrays:

$array1 = array('apple', 'banana', 'pear');
$array2 = array('orange', 'grape', 'kiwi');

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

print_r($mergedArray);

The output result is:

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

Method 2: Use the addition operator ( )

In PHP, you can use the addition operator () to merge two arrays. This operator merges the elements of two arrays into a new array.

The following is a code example that uses the addition operator to merge two arrays:

$array1 = array('apple', 'banana', 'pear');
$array2 = array('orange', 'grape', 'kiwi');

$mergedArray = $array1 + $array2;

print_r($mergedArray);

The output result is:

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

It should be noted that if the same exists in the two arrays key names, the addition operator will retain the values ​​in the first array and ignore the values ​​in the second array.

Method 3: Use the array_merge_recursive function

The array_merge_recursive function is a function that recursively merges arrays. It can recursively merge two or more arrays and return a new array. Unlike the array_merge function, the array_merge_recursive function does not simply merge elements with the same key name directly, but converts them into a subarray containing the same key name.

The following is a code example of using the array_merge_recursive function to merge two arrays:

$array1 = array('apple', 'banana', 'pear');
$array2 = array('orange', 'grape', 'kiwi');

$mergedArray = array_merge_recursive($array1, $array2);

print_r($mergedArray);

The output result is:

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

As mentioned above, the array_merge_recursive function will merge elements with the same key name Convert to a subarray, which may be what we want in some cases.

Summary:

This article introduces three commonly used array merging methods in PHP: using the array_merge function, using the addition operator (), and using the array_merge_recursive function. According to different needs, choosing the appropriate method can more conveniently implement array merging operations.

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