Introduction to the usage of PHP array_merge() function

In PHP programming, array is a very commonly used and important data type. Array merging is an operation often used in PHP, and the array_merge() function is a very practical array merging function. The following is an introduction to how to use the array_merge() function.

1. What is the array_merge() function?

The array_merge() function is a PHP function used to merge one or more arrays into a new array. It can accept one or more arrays as parameters and merge these arrays into a new array in the order of parameters. The return value of this function is the new merged array.

2. How to use the array_merge() function

Function syntax:

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

The parameters of the array_merge() function can be one or more arrays. Here are several usage examples:

(1) Merge two arrays

$array1 = array("red", "green");
$array2 = array("blue", "yellow");
$result = array_merge($array1, $array2);
// 输出结果为： Array ( [0] => red [1] => green [2] => blue [3] => yellow )

(2) Merge multiple arrays

$array1 = array("red", "green");
$array2 = array("blue", "yellow");
$array3 = array("orange", "purple");
$result = array_merge($array1, $array2, $array3);
// 输出结果为： Array ( [0] => red [1] => green [2] => blue [3] => yellow [4] => orange [5] => purple )

It should be noted that when When the merged arrays have the same keys (i.e. array subscripts), the later arrays will overwrite the values ​​corresponding to the same keys in the previous arrays.

$array1 = array("color" => "red", 2, 4);
$array2 = array("a", "b", "color" => "green", "shape" => "trapezoid", 4);
$result = array_merge($array1, $array2);
// 输出结果为： Array ( [color] => green [0] => 2 [1] => 4 [2] => a [3] => b [shape] => trapezoid [4] => 4 )

3. Summary

The array_merge() function is a very practical array merging function in PHP. It can merge one or more arrays into a new array. This function is simple to use and is often used in array operations. It should be noted that when the merged arrays have the same keys, the latter array will overwrite the values ​​corresponding to the same keys in the previous array.

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