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English
In PHP programming, when processing two-dimensional arrays, you often encounter situations where you need to find the difference between two arrays. Fortunately, PHP provides powerful built-in functions array_diff() and array_column() , which can help us handle array differences easily. This article will describe how to use these two functions to efficiently handle data differences in two-dimensional arrays.
The array_diff() function is used to compare elements of two or more arrays and return a new array containing differential elements. This function deletes elements that exist in other arrays, retaining only elements that are unique to the first array.
grammar:
array_diff(array $array1, array ...$arrays): array
$array1 : The first array.
$arrays : One or more arrays for comparison.
The array_column() function is used to extract the data of a column from a two-dimensional array and return an array containing all the values of the column. This is very useful when dealing with complex two-dimensional arrays, especially when you only need to process a column of data in the array.
grammar:
array_column(array $array, mixed $column_key, mixed $index_key = null): array
$array : The input 2D array.
$column_key : The key of the column to be extracted.
$index_key : Optional, key to provide a custom index for the result array.
Suppose we have two two-dimensional arrays containing user information, we need to find out the user data in array A and not in array B.
<?php
// ArrayA：User data（Include name、Age and email）
$arrayA = [
['name' => 'Alice', 'age' => 25, 'email' => 'alice@example.com'],
['name' => 'Bob', 'age' => 30, 'email' => 'bob@example.com'],
['name' => 'Charlie', 'age' => 35, 'email' => 'charlie@example.com'],
];
// ArrayB：已有User data
$arrayB = [
['name' => 'Alice', 'age' => 25, 'email' => 'alice@example.com'],
['name' => 'David', 'age' => 40, 'email' => 'david@example.com'],
];
// 提取ArrayA和ArrayBIn-houseemailList
$emailsA = array_column($arrayA, 'email');
$emailsB = array_column($arrayB, 'email');
// usearray_diff()找出在ArrayAmiddle但不在ArrayBIn-houseemail
$diffEmails = array_diff($emailsA, $emailsB);
// Get the difference data（在ArrayAmiddle但不在ArrayBmiddle）
$diffData = [];
foreach ($arrayA as $user) {
if (in_array($user['email'], $diffEmails)) {
$diffData[] = $user;
}
}
// Output differential data
echo "<pre>";
print_r($diffData);
echo "</pre>";
?>
Extract the Email column: We use array_column() to extract the email addresses of all users from a two-dimensional array, generating two arrays $emailsA and $emailsB containing all email addresses.
Find the difference: Then, use the array_diff() function to compare the two email arrays to find the email addresses in $emailsA but not in $emailsB . The returned $diffEmails array contains all the differential emails.
Get the difference data: Finally, we traverse $arrayA to get the user's complete information based on the difference's email address. We check whether each user's email is in $diffEmails through the in_array() function, and if so, add that user information to the $diffData array.
Output result: The result array $diffData contains all user information in array A but not in array B.
According to the above code, the output will be:
Array
(
[0] => Array
(
[name] => Bob
[age] => 30
[email] => bob@example.com
)
[1] => Array
(
[name] => Charlie
[age] => 35
[email] => charlie@example.com
)
)
As shown above, Bob and Charlie are users in array A and not in array B.
