PHP 5.6 function analysis: How to use the array_merge function to merge multiple arrays

PHP 5.6 Function Analysis: How to use the array_merge function to merge multiple arrays

In PHP development, we often encounter situations where multiple arrays need to be merged into one array. PHP provides multiple built-in functions to process arrays, one of which is very practical function is array_merge(). In this article, we will detail how to use the array_merge() function to merge multiple arrays.

First, let's take a look at the basic usage of the array_merge() function. The array_merge() function accepts multiple arrays as parameters and merges the values ​​of these arrays into a new array one by one. Below is the syntax of the array_merge() function:

array_merge(Array $array1 [, Array $... [, Array $...]])

We can call this function by passing multiple arrays as parameters. This function merges arrays in order of parameters. Now, let us demonstrate how to use the array_merge() function through a concrete example.

$array1 = array('a', 'b', 'c');
$array2 = array(1, 2, 3);
$array3 = array('d', 'e', 'f');

$result = array_merge($array1, $array2, $array3);

print_r($result);

Run the above code, we will get the following output:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => 1
    [4] => 2
    [5] => 3
    [6] => d
    [7] => e
    [8] => f
)

As shown above, the array_merge() function merges the three arrays into a new array and merges them according to their parameters. The order was merged.

In addition to merging index arrays, the array_merge() function can also be used to merge associative arrays. The following is an example:

$array1 = array('name' => 'John', 'age' => 25);
$array2 = array('email' => 'john@example.com', 'phone' => '1234567890');

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

print_r($result);

The output result is as follows:

Array
(
    [name] => John
    [age] => 25
    [email] => john@example.com
    [phone] => 1234567890
)

Similarly, the array_merge() function can also successfully merge associative arrays and retain the original key-value pairs.

In addition, there are some things to note about the array_merge() function. First, if the parameters passed to the array_merge() function have the same key name, the value in the subsequent parameter will overwrite the value in the previous parameter. For example:

$array1 = array('a' => 1, 'b' => 2);
$array2 = array('a' => 3, 'c' => 4);

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

print_r($result);

The output is as follows:

Array
(
    [a] => 3
    [b] => 2
    [c] => 4
)

In the above example, the key name 'a' in the subsequent array overwrites the same key name 'a' in the previous array, so ultimately There is only one 'a' key in the merged result, and the corresponding value is 3.

Secondly, the array_merge() function does not re-index the merged array. If the merged array is an indexed array and has the same key name, the merged array will retain the original key name. For example:

$array1 = array('a', 'b', 'c');
$array2 = array(1 => 'd', 2 => 'e', 3 => 'f');

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

print_r($result);

The output result is as follows:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [1] => d
    [2] => e
    [3] => f
)

In the above example, the key names '1' and '2' in the merged array conflict with the key names in the original index array. Therefore, the original key names are retained in the merged array.

Through the introduction of this article, we learned how to use the array_merge() function in PHP 5.6 to merge multiple arrays. Whether merging index arrays or associative arrays, the array_merge() function can meet our needs well. Using this function, we can easily merge multiple arrays, simplifying code writing and processing. I hope this article can be helpful to everyone’s practice in PHP development!

The above is the detailed content of PHP 5.6 function analysis: How to use the array_merge function to merge multiple arrays. For more information, please follow other related articles on the PHP Chinese website!