How to merge two arrays in php after removing duplicate values

Implementation method: 1. Use "array_unique (array)" to remove duplicate values ​​from the two arrays; 2. Use "array_merge_recursive (deduplication array 1, deduplication array 2)" to merge the two deduplications. If the key names are the same, the key values ​​corresponding to the key names will be merged into a sub-array.

The operating environment of this tutorial: windows7 system, PHP8.1 version, DELL G3 computer

php will be two Method for merging arrays after removing duplicate values

Step 1. Use the array_unique() function to remove duplicate values ​​from the two arrays

array_unique( ) function removes duplicate values ​​from an array and returns the resulting array.

• When the values ​​of several array elements are equal, only the first element is retained and the other elements are deleted.

<?php
$arr1=array("a"=>"red","b"=>"green","c"=>"red");
$arr2=array("1"=>"Cat","2"=>"Dog","3"=>"Cat","4"=>"rabbit");
$Narr1=array_unique($arr1);
$Narr2=array_unique($arr2);
var_dump(array_unique($Narr1));
var_dump(array_unique($Narr2));
?>

Step 2. Use the array_merge_recursive() function to merge the two deduplicated arrays

The array_merge_recursive() function is used to merge one or more arrays into one array.

The difference between this function and the array_merge() function is that it handles the case where two or more array elements have the same key name. array_merge_recursive() does not perform key name overwriting, but recursively combines multiple values ​​with the same key name into an array.

• That is, when merging arrays, if the same key is encountered, the value in the key will be merged into a sub-array

<?php
$arr1=array("a"=>"red","b"=>"green","c"=>"red");
$arr2=array("1"=>"Cat","2"=>"Dog","3"=>"Cat","4"=>"rabbit");
$Narr1=array_unique($arr1);
$Narr2=array_unique($arr2);
var_dump(array_unique($Narr1));
var_dump(array_unique($Narr2));

var_dump(array_merge_recursive($Narr1,$Narr2));
?>

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