How to combine multiple arrays into one array in php

PHP is a server-side programming language with rich built-in array functions that can easily operate on arrays. Arrays are a very common data type in PHP, especially when dealing with a lot of data. Sometimes we need to combine two or more arrays into one array. At this time, PHP provides several methods to achieve this goal.

1. Use the array_merge() function

PHP provides a function called array_merge(), which can merge two or more arrays into one array. This function takes all arrays as parameters and returns a new array containing the key-value pairs of all input arrays. The specific usage of this function is as follows:

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

Among them, array1 is the first array,... means it can receive multiple array parameters. The returned value is a merged array.

The following is an example to demonstrate how to use the array_merge() function:

<?php // 定义两个数组
$array1 = array(&#39;a&#39;, &#39;b&#39;, &#39;c&#39;);
$array2 = array(&#39;d&#39;, &#39;e&#39;, &#39;f&#39;);

// 合并两个数组
$result = array_merge($array1, $array2);

// 输出结果
print_r($result);
?>

The output of the above code is as follows:

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

2. Use the " " operator

You can also use the " " operator to merge arrays in PHP. This operator combines the values ​​of two arrays into a new array. If there are duplicate key names in two arrays, the value of the later array will overwrite the previous value. For example:

<?php $array1 = array(&#39;a&#39;, &#39;b&#39;, &#39;c&#39;);
$array2 = array(&#39;c&#39;, &#39;d&#39;, &#39;e&#39;);

$result = $array1 + $array2;

print_r($result);
?>

The output of the above code is as follows:

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

3. Use the array_merge_recursive() function

Different from the array_merge() function, the array_merge_recursive() function can merge Values ​​in arrays with the same key name. If array key names can only be provided as numbers or strings, this function will perform as described below, merging the arrays into a new array:

1. If the indices of both arrays are is numeric, the merge creates a new numeric-indexed array containing the values ​​of both original arrays.
2. If the keys of two arrays are strings, the value of the first array will be overwritten with the value of the second array. For example, if the first array contains the key "name" and the second array also contains the key "name", the values ​​in the second array will overwrite the values ​​in the first array.

The following is an example of using the array_merge_recursive() function:

<?php $arr1 = array(&#39;name&#39; => 'Peter');
$arr2 = array('name' => 'John', 'age' => 25);

$arr3 = array_merge_recursive($arr1, $arr2);

print_r($arr3);
?>

The output of the above code is as follows:

Array
(
    [name] => Array
        (
            [0] => Peter
            [1] => John
        )

    [age] => 25
)

4. Use the " " operator and array_replace( ) Function

First, use the " " operator to combine the two arrays into a new array. Second, use the array_replace() function to replace the values ​​of one array with the values ​​of another array. For example:

<?php $arr1 = array(&#39;name&#39; => 'Peter', 'age' => 30);
$arr2 = array('name' => 'John');

$arr3 = $arr2 + $arr1;

$arr3 = array_replace($arr1, $arr2);

print_r($arr3);
?>

The output of the above code is as follows:

Array
(
    [name] => John
    [age] => 30
)

Summary

In PHP, there are many ways to combine two or more arrays into one array . Two arrays can be simply combined using the array_merge() function. You can use the " " operator to combine the values ​​of two arrays into a new array. The array_merge_recursive() function can merge values ​​in arrays with the same key name. Use the array_replace() function to replace the values ​​of one array with the values ​​of another array. According to different needs and scenarios, choosing the appropriate method to perform array merging operations will greatly improve the development efficiency and performance of PHP programs.

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