Will adding php arrays merge duplicate values?

php array addition will not merge duplicate values. In PHP, you can use the " " operator to add one or more arrays. These arrays will be merged to return a new array. The syntax is "array 1 array 2..". The elements of the subsequent arrays will be appended to the end of the first element. , it has no effect whether the value is repeated; but if the key name is repeated, the previous element will overwrite the following element.

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

php array addition will not be merged Duplicate value.

In PHP, you can use the " " operator to add one or more arrays, and these arrays will be merged to return a new array; syntax:

数组1+数组2+...

The following array The element will be appended to the end of the first element

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr1=array("a1"=>1,"a2"=>2,"a3"=>3,"a4"=>4,"a5"=>5);
$arr2=array("b1"=>6,"b2"=>5,"b3"=>4,"b4"=>3,"b5"=>2,"b6"=>1);
var_dump($arr1);
var_dump($arr2);
$arr=$arr1+$arr2;
var_dump($arr);
?>

It can be seen that whether the value is repeated has no effect, and duplicate values ​​will not be merged.

But repeated key names will have an impact. If the key names are repeated, the previous elements will overwrite the following elements

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr1 = array("a" => "apple", "b" => "banana");
$arr2 = array("a" => "pear", "b" => "strawberry", "c" => "cherry");
var_dump($arr1);
var_dump($arr2);
$arr=$arr1+$arr2;
var_dump($arr);
?>

Recommended study: " PHP video tutorial》

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