PHP array key value reversal: exploration of efficient solutions

Array key-value reversal can be achieved in PHP through a variety of efficient methods: use the array_flip() function to directly exchange keys and values. Write a custom function to combine values ​​and keys into a new array using array_combine(). Use the mapping functions array_map() and array_column() to convert array structures and recombine them. Performance comparison shows that the array_flip() function is fastest in small arrays, while custom functions and mapping functions have advantages when the array size is larger.

PHP array key value reversal: efficient solution exploration

Array key value reversal, that is, exchanging the keys and values ​​in the array, This is a common operation in PHP. This article will explore several efficient solutions and demonstrate them through practical cases.

Method 1: array_flip() function

$array = ['name' => 'John Doe', 'age' => 30];
$flipped_array = array_flip($array);
print_r($flipped_array);

Output:

Array
(
    [John Doe] => name
    [30] => age
)

Method 2: Custom function

function flip_array($array) {
    return array_combine(array_values($array), array_keys($array));
}

$array = ['name' => 'John Doe', 'age' => 30];
$flipped_array = flip_array($array);
print_r($flipped_array);

Output:

Array
(
    [John Doe] => name
    [30] => age
)

Method 3: Mapping function

$array = ['name' => 'John Doe', 'age' => 30];
$flipped_array = array_map(function($key, $value) { return [$value, $key]; }, array_keys($array), array_values($array));
$flipped_array = array_combine(array_column($flipped_array, 0), array_column($flipped_array, 1));
print_r($flipped_array);

Output:

Array
(
    [John Doe] => name
    [30] => age
)

Performance comparison

When the array size is small, the array_flip() function is the fastest. For larger arrays, custom functions and mapping functions have better performance.

Practical case

Array key value reversal can be used in various scenarios, for example:

• From user ID to user name Mapping
• Mapping from country code to country name
• Create an inverted index to increase search speed

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