How to merge arrays in php

When developing PHP applications, you may frequently use the array data type. Sometimes, you may need to combine two or more groups into one. PHP provides you with a built-in function that can be used to merge any number of arrays. In this article, we will take an in-depth look at how to merge arrays in PHP.

Use the array_merge() function to merge arrays

PHP provides a simple and powerful function array_merge(), which can be used to merge two or more arrays. The syntax of this function is as follows:

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

This function accepts two or more arrays as parameters and returns a new array containing the elements of all arrays. Note that this function does not modify the original array, but returns a new array.

Here is some sample code that demonstrates how to merge two PHP arrays using the array_merge() function:

//定义两个数组
$array1 = array('red', 'green');
$array2 = array('blue', 'yellow');

//将两个数组合并成一个数组
$result = array_merge($array1, $array2);

//输出结果
print_r($result);

The above code will output:

Array
(
    [0] => red
    [1] => green
    [2] => blue
    [3] => yellow
)

Merge arrays using operators

In addition to the array_merge() function, PHP also provides an easy way to merge two arrays - using operators. This operator is similar to a function that merges two arrays together and returns a new array. Its general syntax is as follows:

array1 + array2

This will return a new array containing all elements of both arrays. However, when merging arrays using the operator, the values ​​of elements with duplicate key names will not be overwritten. In this case, the first occurring element value will be retained.

Here is an example demonstrating how to merge arrays using this operator in PHP:

//定义两个数组
$array1 = array('a' => 'apple', 'b' => 'banana');
$array2 = array('b' => 'blueberry', 'c' => 'cherry');

//将两个数组合并成一个数组
$result = $array1 + $array2;

//输出结果
print_r($result);

The result will be:

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

In this example, the second array The value of the 'b' key in is ignored because it is the same as the 'b' key in the first array.

Use the array_replace() function to merge arrays

In addition to array_merge() and the operator, PHP also provides the array_replace() function. The function takes one array as the main array and the remaining arrays as additional arguments, and replaces any duplicate elements in them with the following elements. The following is the syntax of the function:

array array_replace ( array $array1 , array $array2 [, array $... ] )

Please see the following example:

//定义两个数组
$array1 = array('a' => 'apple', 'b' => 'banana');
$array2 = array('b' => 'blackberry', 'c' => 'cherry');

//将两个数组合并成一个数组
$result = array_replace($array1, $array2);

//输出结果
print_r($result);

The output is:

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

In this example, the 'b of the second array ' key is used to replace the 'b' key in the first array.

Summary

Combining arrays is a common task in PHP development. This article describes three different ways to merge arrays - the array_merge() function, the operator and the array_replace() function. You can choose one of these methods based on your needs and preferences.

No matter which method you choose, remember that the result of the merge is a new array and the original array is not affected. Now that you know how to merge arrays in PHP, start using it in your applications!

The above is the detailed content of How to merge arrays in php. For more information, please follow other related articles on the PHP Chinese website!