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In PHP, array operations are one of the most common tasks in daily development. PHP provides a rich array operation function, where array_diff_assoc() and array_merge() are two very useful functions. These two functions are very useful when we need to compare two arrays and process their differences, or do specific filtering and processing when merging the arrays.
This article will introduce how to use array_diff_assoc() and array_merge() union to handle array changes and solve array differences and merge problems. We will use a practical example to explain how these two functions work together.
The array_diff_assoc() function is used to compare two arrays, returning an array that is contained in the first array, but not in other arrays. Unlike array_diff() , array_diff_assoc() will take into account both the key name and value of the array, and only elements with completely different key-value pairs will be returned.
array_diff_assoc(array $array1, array $array2, array ...$arrays): array
array1 : The first array that needs to be compared.
array2 : The second array that needs to be compared with the first array.
Return: Returns a new array containing key-value pairs that are in array1 but not in array2 .
$array1 = [
"a" => 1,
"b" => 2,
"c" => 3
];
$array2 = [
"a" => 1,
"b" => 4,
"c" => 3
];
$result = array_diff_assoc($array1, $array2);
print_r($result);
Output:
Array
(
[b] => 2
)
As can be seen from the result, the array_diff_assoc() function only returns elements with different values on the key name b .
The array_merge() function is used to merge one or more arrays. It returns a new array containing all the elements of the array. If multiple arrays have the same key names, the subsequent array element will overwrite the previous array element.
array_merge(array ...$arrays): array
$arrays : One or more arrays that need to be merged.
Return: Returns a new array containing all input array elements.
$array1 = [
"a" => 1,
"b" => 2
];
$array2 = [
"c" => 3,
"d" => 4
];
$result = array_merge($array1, $array2);
print_r($result);
Output:
Array
(
[a] => 1
[b] => 2
[c] => 3
[d] => 4
)
As shown above, array_merge() combines two arrays into a new array.
Suppose we have two arrays, one is the original data array and the other is the data array after some changes. We need to find out the differences between these two arrays and merge the differences parts together. This process can be achieved by array_diff_assoc() and then merge arrays using array_merge() .
// Raw data
$original = [
"name" => "John",
"email" => "john@example.com",
"age" => 30
];
// Changes
$updated = [
"name" => "John",
"email" => "john@m66.net", // Modified email address
"city" => "New York" // New city added
];
// use array_diff_assoc Find the difference
$diff = array_diff_assoc($updated, $original);
// Merge the Differences
$merged = array_merge($original, $diff);
print_r($merged);
Output:
Array
(
[name] => John
[email] => john@m66.net
[age] => 30
[city] => New York
)
Find the difference : array_diff_assoc() is used to find the difference between updated array and original array. It will return a new array containing different key-value pairs (such as email and city ).
Merge Difference : array_merge() is used to merge the original array and the diff parts. Through the merge operation, we can keep the other parts of the original array while merging the updated parts (differences) in.
This technique is particularly suitable for handling configuration updates or comparisons of database records. For example, when you need to detect changes in configuration files, user settings or database records, you can find all the different parts through array_diff_assoc() , and then use array_merge() to merge the new values into the original data, which can efficiently update the array.
By combining array_diff_assoc() and array_merge() , we can easily handle differences between arrays and merge them. array_diff_assoc() helps us find the differences between arrays, while array_merge() is able to merge these differences into the original data. Both are used in conjunction with each other and are particularly suitable for scenarios where data changes and combinations are required.
I hope this article can help you better understand the use of these two functions and flexibly apply them in actual projects. If you have any questions or ideas, please leave a message to discuss!
