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Blacklist filtering is a common requirement during development. Suppose we have a user access data, we want to exclude some blacklisted users, or filter out inappropriate access based on certain conditions. At this time, the array_diff_ukey() function can come in handy. It can be compared based on the key names of the array, thus helping us implement the blacklist filtering mechanism.
The array_diff_ukey() function is a built-in function in PHP that compares two arrays based on the key name and returns different parts of the two arrays. Its basic syntax is as follows:
array_diff_ukey(array $array1, array $array2, callable $key_compare_func): array
$array1 : The first array.
$array2 : The second array.
$key_compare_func : A callback function that compares the key names of two arrays and returns a boolean value indicating whether the two key names are equal.
In actual blacklist filtering applications, we can use this function to filter out users on the blacklist. Next, we will use an example to show in detail how to use array_diff_ukey() to implement the blacklist filtering mechanism.
Suppose we have two arrays, one is the user access record array, and the other is the blacklist array, and we want to filter out the users on the blacklist.
<?php
// User access record array，Key for userID，The value is the user's access record
$accessLogs = [
1 => "Access history1",
2 => "Access history2",
3 => "Access history3",
4 => "Access history4",
5 => "Access history5"
];
// Blacklist array，The key is blacklisted userID
$blacklist = [
2 => "Blacklisted users",
4 => "Blacklisted users"
];
// Custom key comparison function，Determine whether the two key names are equal
function compare_keys($key1, $key2) {
return $key1 - $key2;
}
// use array_diff_ukey Function filters out users on the blacklist
$filteredLogs = array_diff_ukey($accessLogs, $blacklist, 'compare_keys');
// 输出过滤后的Access history
print_r($filteredLogs);
?>
We first define two arrays, $accessLogs is an array containing user access records, and $blacklist is a blacklist array. The keys of both arrays are user IDs.
Next, we define a function called compare_keys to compare whether the two key names are equal. This function is used for the callback parameter of the array_diff_ukey() function, and returns a boolean value to determine whether the two keys are equal.
Then, use the array_diff_ukey() function to filter out users in the blacklist array and return a new filtered array $filteredLogs that contains users not in the blacklist.
Finally, the filtered result is output through print_r() .
Array
(
[1] => Access history1
[3] => Access history3
[5] => Access history5
)
As shown above, users in the blacklist (IDs 2 and 4) have been successfully filtered out, and the remaining access records only contain non-blacklist users.
This method can be used in multiple scenarios, such as:
Website user access log filtering to avoid access by blacklisted users.
Filter certain unauthorized IP addresses to ensure that the system only receives legitimate requests.
In the user management system, some disabled users are removed from the list of available users.
Through the array_diff_ukey() function in PHP, we can efficiently implement the blacklist filtering mechanism. Combined with the customized key comparison function, you can flexibly compare the key names of the array to achieve accurate filtering of users or data. If similar operations are required in actual development, the array_diff_ukey() function is undoubtedly a very practical tool.
