How to merge PHP arrays?

How to merge arrays in PHP?

First of all, let’s introduce what array_merge() is: it merges an array unit or multiple array units. The value in an array is added to the previous one. After the array, return the resulting array.

In the previous article "Interception, equal division and replacement of partial arrays in PHP arrays", we introduced the cutting, equal division and replacement of arrays. I believe everyone should be able to After understanding some related function operations of PHP arrays, today we will continue to explain another function to you: array_merge().

array_merge() syntax structure is as follows:

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

Next let’s introduce the usage of array_merge():

1. Assume that the string key in the input array If the names are the same, then the key value of the key is the value corresponding to the last key name. Everyone should pay attention here, the subsequent value will overwrite the previous same value! The specific code is as follows:

<?php
header("Content-Type:text/html; charset=utf-8");
$array = array("name"=>"PHP中文网","id"=>"www.php.cn");
$arr = array("name1"=>"网站","id"=>"网址");
$array1=array_merge($array,$arr);
print_r($array1);
?>

The output result is:

2. If an array is a numeric key name, then the key name will be Re-index in a continuous manner, then the subsequent value will not overwrite the original value, but will be appended to the end. The specific code is as follows:

<?php
header("Content-Type:text/html; charset=utf-8");
$array = array(1=>"PHP中文网",2=>"www.php.cn");
$arr = array(3=>"网站",4=>"网址");
$array1=array_merge($array,$arr);
print_r($array1);
?>

The output result is:

3. If the array_merge() function only inputs an array, and the key value is an integer If so, the function will return a new array with integer key names, and the key names will be re-indexed starting from 0. The specific code is as follows:

<?php
header("Content-Type:text/html; charset=utf-8");
$array = array(10=>"PHP中文网",20=>"www.php.cn",3=>"网址",50=>"网站");
$array1=array_merge($array);
print_r($array1);
?>

The output result is as follows:

4. Assume that the key name in the element after the array is the same as the key name in the previous array element When, then the key value of the corresponding key name in the result array will be overwritten by the later one, and the key value will also be the later one! The specific code is as follows:

<?php
header("Content-Type:text/html; charset=utf-8");
$array = array("name"=>"PHP中文网","id"=>"www.php.cn");
$arr = array("name"=>"网站","id"=>"网址");
$array1=array_merge($array,$arr);
print_r($array1);
?>

The output result is as follows:

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《Interception of PHP array, equal division and replacement of part of the array 》

《Reverse order of PHP array》

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