Using PHP array_flip() to Reverse Array Keys and Values

In PHP, the array_flip() function is commonly used to invert an array's keys and values, returning a new array where each original value becomes a key and each original key becomes its corresponding value.

Basic Syntax:

<code>array array_flip ( array $array )</code>

Parameter:

The $array parameter is the array to be flipped.

Return Value:

The function returns the flipped array; if the argument is not a valid array, it returns bool(false) . Below is an example of using array_flip() :

<code>$array = array('a' => 'apple', 'b' => 'banana', 'c' => 'cherry');
$flippedArray = array_flip($array);
print_r($flippedArray);
</code>

Output:

<code>Array
(
    [apple] => a
    [banana] => b
    [cherry] => c
)
</code>

If the original array contains duplicate values, only the last key will be kept in the flipped array, as demonstrated in the following example where two keys share the value “banana”:

<code>$array = array('a' => 'apple', 'b' => 'banana', 'c' => 'banana');
$flippedArray = array_flip($array);
print_r($flippedArray);
</code>

Output:

<code>Array
(
    [apple] => a
    [banana] => c
)
</code>

When using array_flip() , ensure that the original array's values are unique or can be used as unique string keys; otherwise the result may not be as expected.