Current Location: Home> Latest Articles> Comparison and detection of user preference settings

Comparison and detection of user preference settings

M66 2025-06-06

In web development, user preferences are a common need for applications, especially in social platforms or e-commerce websites. Users can usually adjust the application's functions, interface or notification settings according to their needs. When users update their preferences, developers need a way to detect differences between old and new settings in order to record changes, analyze user behavior, or provide reference for subsequent operations.

In PHP, the array_diff_assoc function is a very practical tool for comparing two arrays and returning their differences. This function not only compares the values ​​of the array, but also checks whether the keys of the array match. Therefore, array_diff_assoc can effectively help us detect the differences in user preference settings before and after updates.

1. Basic usage of array_diff_assoc function

The function of the array_diff_assoc function is to return an array containing key-value pairs that are in the first array but not in the second array. Unlike array_diff , array_diff_assoc not only compares values, but also considers the differences in keys.

Function prototype:

 array_diff_assoc(array $array1, array $array2) : array

  • $array1 : The first array to compare.

  • $array2 : The second array that needs to be compared.

The function returns a new array containing key-value pairs that exist in $array1 and not in $array2 . If the two arrays are the same on values ​​or keys, no difference is returned.

2. Use array_diff_assoc to detect user preference differences

Suppose we have a user's old preferences and new preferences in the app, here is a simple example:

Old settings ( $oldSettings ):

 $oldSettings = [
    'theme' => 'dark',
    'notifications' => true,
    'language' => 'en'
];

New Settings ( $newSettings ):

 $newSettings = [
    'theme' => 'light',
    'notifications' => false,
    'language' => 'fr'
];

We can use the array_diff_assoc function to compare the differences between these two settings arrays:

 $differences = array_diff_assoc($oldSettings, $newSettings);
print_r($differences);

Output result:

 Array
(
    [theme] => dark
    [notifications] => 1
    [language] => en
)

3. Results analysis

The above code returns an array containing key-value pairs that exist in $oldSettings but not in $newSettings . With this information, we can clearly see which preferences have changed.

  • The theme changed from 'dark' to 'light' .

  • notifications changed from true to false .

  • language changed from 'en' to 'fr' .

4. Practical application scenario: record preference settings changes

Suppose we want to record changes in user preferences for subsequent analysis or for generation of user behavior reports. The difference information can be stored in the database or a change log can be generated. The code is as follows:

 $differences = array_diff_assoc($oldSettings, $newSettings);

if (!empty($differences)) {
    // Suppose we have a logging function to record changes in user preference settings
    logPreferenceChange($userId, $differences);
}

function logPreferenceChange($userId, $changes) {
    // Assume that changes are stored in some way
    echo "user {$userId} The preferences have changed：\n";
    print_r($changes);
}

5. More complex scenarios: URL data comparison

In some scenarios, user preferences may involve URL links. Suppose we have the following URL fields that need to be compared:

URL in old settings:

 $oldSettings = [
    'profile_url' => 'https://oldsite.com/user/profile',
    'dashboard_url' => 'https://oldsite.com/user/dashboard'
];

URL in new settings:

 $newSettings = [
    'profile_url' => 'https://newsite.com/user/profile',
    'dashboard_url' => 'https://newsite.com/user/dashboard'
];

We can replace the URL domain name part in the old and new settings with a unified domain name, such as m66.net , to avoid misjudgment caused by different domain names. The following is the implementation code:

Related