How to merge values ​​of php multidimensional arrays

In the PHP development process, multi-dimensional arrays are often used. They are composed of multiple nested arrays and can save a large amount of data. However, in some cases, we need to combine all the values ​​​​in the array. At this time, we need to use some functions provided by PHP to achieve this.

There are two situations where array merging is required. The first is to merge the same key-value pairs together, so that duplication of key-value pairs can be prevented during array processing. The second case is to merge all the values ​​in the multidimensional array together, so that the values ​​in different arrays can be merged into one array.

The following are the specific implementation methods for the two situations.

First case:

We can use the array_merge function to merge the key-value pairs in the two arrays together. However, if the key value is duplicated, the latter will overwrite the former. This method can only merge arrays of the same dimension.

Sample code:

$array1 = array('a' => 'apple', 'b' => 'banana');
$array2 = array('c' => 'cherry', 'b' => 'blueberry');
$result = array_merge($array1, $array2);
print_r($result);

The output of the above code is:

Array
(
    [a] => apple
    [b] => blueberry
    [c] => cherry
)

You can see that because the 'b'=>'blueberry' key in the $array2 array The value is duplicated with the 'b'=>'banana' key value in the $array1 array, so the value of the 'b' key value in the final output becomes 'blueberry'.

Second case:

We can use the array_merge_recursive function to merge all the values ​​​​in two or more multi-dimensional arrays into one array without overwriting the same key-value pairs. is to recursively merge values ​​and subarrays together.

Sample code:

$array1 = array('red' => array('apple', 'strawberry'), 'green' => 'kiwi');
$array2 = array('blue' => array('blueberry', 'grape'), 'red' => 'cherry');
$result = array_merge_recursive($array1, $array2);
print_r($result);

The output of the above code is:

Array
(
    [red] => Array
        (
            [0] => apple
            [1] => strawberry
            [2] => cherry
        )

    [green] => kiwi
    [blue] => Array
        (
            [0] => blueberry
            [1] => grape
        )

)

As you can see, since the 'red' key value in the $array2 array is in the $array1 array already exists, so the key-value pair 'red'=>'cherry' in the $array2 array is added to the array of red key-values.

Using the above two methods, you can easily merge key-value pairs and values ​​in PHP multi-dimensional arrays to process data more efficiently.

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