How to convert array value to key in php

3 methods: 1. Use the "array_flip($arr)" statement; 2. Use the "array_combine($arr,array_keys($arr))" statement; 3. Use "foreach($arr1 as $ k=>$v){$arr2[$v]=$k;}" statement.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

php converts the array value into key, that is Convert the keys and values ​​in the array to each other. Three methods are introduced below:

Method 1: Use array_flip() function

array_flip() function can exchange keys and values ​​​​in the array

<?php
$arr1=array("aaa"=>11,"bbb"=>22,"ccc"=>33);
var_dump($arr1);
$arr2=array_flip($arr1);
var_dump($arr2);
?>

Method 2: Use array_keys() array_combine() function

Implementation idea:

• Use array_keys () Obtain the key name in the array and return the key name array

• Use array_combine() to use the original array as the key name and the key name array as the key value to merge into a new array

<?php
$arr=array("Peter"=>11,"Ben"=>22,"Joe"=>33);
var_dump($arr);
$keys=array_keys($arr);
var_dump(array_combine($arr,$keys));
?>

Method 3: Using a foreach loop and an empty array

<?php
$arr1=array("aaa"=>11,"bbb"=>22,"ccc"=>33);
$arr2=array();
foreach($arr1 as $k=>$v){
    $arr2[$v]=$k;
}
var_dump($arr2);
?>

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