How to filter specific block data with array_chunk in combination with array_filter

In PHP, array_chunk and array_filter are very useful functions. array_chunk can cut a large array into small pieces, while array_filter can apply filtering conditions to each element in the array, retaining elements that meet the conditions. Combining these two functions, it is possible to efficiently filter data by block.

Array chunk filtering using array_chunk and array_filter

Suppose we have an array with a large number of elements, and we want to slice the array by a certain block size, and only elements that meet certain conditions are retained. Then, we can use array_chunk to slice, and then use array_filter to filter the elements in each slice.

Example: Filter out users over 18 years of age from user array

Suppose we have an array of users that contain the user's name and age, and we need to filter out users older than or equal to 18 years old by block.

 <?php

// Raw data array
$users = [
    ['name' => 'Alice', 'age' => 25],
    ['name' => 'Bob', 'age' => 17],
    ['name' => 'Charlie', 'age' => 20],
    ['name' => 'David', 'age' => 15],
    ['name' => 'Eva', 'age' => 22],
    ['name' => 'Frank', 'age' => 19],
];

// Split array by block
$chunks = array_chunk($users, 2); // Each block contains 2 A user

// Filter each piece，Retain age >= 18 Users
$filteredChunks = array_map(function($chunk) {
    return array_filter($chunk, function($user) {
        return $user['age'] >= 18;
    });
}, $chunks);

// Print filtered results
print_r($filteredChunks);

?>

explain:

1. array_chunk($users, 2) divides the original user array into small arrays containing 2 users per block.

2. array_map allows us to apply the array_filter function to each small array (i.e., each piece of data).

3. array_filter filters out users who meet the age requirements based on the conditions of user['age'] >= 18 .

4. Finally, the $filteredChunks array will contain the filtered data for each block.

Output:

 Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [name] => Alice
                    [age] => 25
                )

            [2] => Array
                (
                    [name] => Charlie
                    [age] => 20
                )
        )

    [1] => Array
        (
            [4] => Array
                (
                    [name] => Eva
                    [age] => 22
                )

            [5] => Array
                (
                    [name] => Frank
                    [age] => 19
                )
        )
)

Further optimization: Use custom filtering conditions

You can modify the filter conditions according to actual conditions to meet different needs. For example, if we want to filter out users between 18 and 30 years old, we can adjust the filtering function:

 $filteredChunks = array_map(function($chunk) {
    return array_filter($chunk, function($user) {
        return $user['age'] >= 18 && $user['age'] <= 30;
    });
}, $chunks);

In this way, you can flexibly handle different filtering needs.

Summarize

Through the combination of array_chunk and array_filter , we can easily process large arrays in chunks and perform conditional filtering within each block. This method is suitable for processing large amounts of data, which can effectively reduce memory consumption and improve performance, while also making the code more concise and easy to understand.

Hope this article will be helpful for you to understand the usage of array_chunk and array_filter ! If you have any questions or are interested in other PHP functions, please visit our website!