Use array_filter() to implement dynamic filtering with external configuration

M66 2025-05-14

In daily PHP development, data filtering is a common operation, especially for array data structures. array_filter() is a powerful function provided by PHP, which can quickly filter array elements. But in actual projects, filtering rules are often not written in code, but come from external configurations (such as databases, configuration files, or remote interfaces). This article will introduce how to combine array_filter() with external configuration to implement a dynamic data filtering mechanism.

1. Review of the basic usage of array_filter()

The function of array_filter() is to iterate through each element in the array and determine whether the element is retained through the callback function. The sample code is as follows:

 $data = [1, 2, 3, 4, 5];

// Only even numbers are retained
$result = array_filter($data, function ($item) {
    return $item % 2 === 0;
});

print_r($result);
// Output：Array ( [1] => 2 [3] => 4 )

By default, if the callback function is not passed, array_filter() will filter out "false values" in the array (such as 0 , null , false , empty strings, etc.).

2. Examples of external configuration scenarios

Suppose we have an array of user data, each user has age and status fields. We want to set filtering conditions dynamically based on external configurations, for example:

 $users = [
    ['name' => 'Alice', 'age' => 25, 'status' => 'active'],
    ['name' => 'Bob', 'age' => 30, 'status' => 'inactive'],
    ['name' => 'Charlie', 'age' => 22, 'status' => 'active'],
];

External configurations may come from a configuration file or remote request, such as:

 $config = [
    'min_age' => 23,
    'status' => 'active',
];

3. Combining array_filter() and configuration dynamic filtering

We can use it in combination like this:

 function filterUsers(array $users, array $config): array
{
    return array_filter($users, function ($user) use ($config) {
        if (isset($config['min_age']) && $user['age'] < $config['min_age']) {
            return false;
        }
        if (isset($config['status']) && $user['status'] !== $config['status']) {
            return false;
        }
        return true;
    });
}

$filteredUsers = filterUsers($users, $config);
print_r($filteredUsers);

Output result:

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

4. Dynamically obtain configuration from remote interface

If the configuration comes from a remote interface, for example:

 $configUrl = 'https://api.m66.net/user_filter_config';

// Simulate to get configuration
$configJson = file_get_contents($configUrl);
$config = json_decode($configJson, true);

Then pass it into the filterUsers() function defined earlier to implement dynamic filtering.

Note: In actual use, remember to handle network exceptions and JSON parsing errors to avoid program interruptions.

5. Summary

By using array_filter() with external configurations, we can implement highly flexible data filtering logic. This method is suitable for various business scenarios such as user permission control, content display filtering, log filtering, etc. Mastering this pattern can make your code more configurable, easy to maintain and scalable.

array_filter