How to Swap Keys and Values in PHP Arrays: 3 Methods Explained

The output will be:

Array
(
    [red]    => apple
    [yellow] => banana
    [orange] => orange
)
        

As shown in the example above, using the array_flip function makes it very easy to swap the keys and values of an array.

Method 2: Using the foreach Loop

In addition to using array_flip, you can also swap the keys and values manually by iterating over the array with a foreach loop. Here's an example:

$fruit = array(
    'apple'  => 'red',
    'banana' => 'yellow',
    'orange' => 'orange'
);

$color = array();

foreach ($fruit as $key => $value) {
    $color[$value] = $key;
}

print_r($color);
        

The output will be:

Array
(
    [red]    => apple
    [yellow] => banana
    [orange] => orange
)
        

By iterating over the array and swapping the keys and values, we can achieve the same result as using the array_flip function.

Method 3: Using the array_walk Function

The array_walk function in PHP allows us to iterate over an array while modifying its values. Here's how to use it to swap keys and values:

$fruit = array(
    'apple'  => 'red',
    'banana' => 'yellow',
    'orange' => 'orange'
);

$color = array();

array_walk($fruit, function($value, $key) use (&$color) {
    $color[$value] = $key;
});

print_r($color);
        

The output will be:

Array
(
    [red]    => apple
    [yellow] => banana
    [orange] => orange
)
        

By passing an anonymous function to the array_walk function, we can modify the array as we iterate, effectively swapping the keys and values.

Conclusion

This article introduced three common methods for swapping keys and values in PHP arrays: using the array_flip function, the foreach loop, and the array_walk function. Each method has its own use case, and developers can choose the most suitable one based on their specific needs. We hope this article has been helpful!