How to invert array key values ​​in php

In PHP, use the array_flip() function to invert the keys and values ​​of an array. This is a very convenient function because we can use this function to re-index the entire array without affecting the array values.

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

$original_array = array("a" => 1, "b" => 2, "c" => 3);
$flipped_array = array_flip($original_array);

print_r($flipped_array);

Output:

Array
(
    [1] => a
    [2] => b
    [3] => c
)

In the above example, we first created an array containing three key-value pairs An array where the values ​​for each key are 1, 2, and 3 respectively. We then use the array_flip() function to flip the keys and values ​​in the original array and store the result in the $flipped_array variable. Finally, we output the reversed array using the print_r() function.

As can be seen from the output results, the keys "a", "b" and "c" in the original array were successfully converted into values ​​in the new array, and the values ​​​​1, 2 and 3 in the original array is used as the key in the new array. In this way, we have successfully inverted the keys and values ​​of the array, making the original array easier to process and operate.

It should be noted that if there are two or more elements in the original array with the same value, problems may occur when executing the array_flip() function. This is because in the new array, each value can only correspond to one key, and for elements with the same value in the original array, only the key of the last element will be retained in the new array. Therefore, when using the array_flip() function, we should ensure that the values ​​in the original array are unique.

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