The array_flip method exchanges the keys and values of an array. This means all the keys are converted to values and all the values are converted to keys.
array_flip(array $array_to_flip): array
This method returns a new array.
<?php$arr = array(1 => "one", 2 => "two", 3 => "three");echo "The array is \n";print_r($arr);echo "\nAfter Flipping \n ";print_r(array_flip($arr));?>
In the code above, we created an array.
one => 1
two => 2
three => 3
We then call the array_flip method by passing the created array, which will flip the keys and values of the passed array and return a new array. The returned array will be:
1 => one
2 => two
3 => three
Make sure all the values of the passed array are either string or integer values, otherwise a warning will be thrown and the value will be skipped. For example:
<?php$arr = array(1 => "one", 2 => array());print_r(array_flip($arr));?>
In the code above, the value for the key 2 is an array, which cannot be used as a key, so we will get a warning and that entry will be skipped. The returned array from the array_flip method will be:
one => 1