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In PHP programming, it is often necessary to perform merging and differentiating operations on arrays. array_diff_key() and array_merge() are two very useful functions in PHP that can help us implement differential merging of arrays. Today, we will dig into these two functions and demonstrate how to merge the differences in the array through them.
array_diff_key() is a key used to compare two or more arrays and returns an array containing different key names. The syntax is as follows:
array_diff_key(array $array1, array $array2, array ...$arrays): array
This function returns an array containing all keys in $array1 , but excludes keys that also exist in other arrays.
The array_merge() function is used to merge two or more arrays. It combines multiple numbers into a new array and returns the merged result. The basic syntax is as follows:
array_merge(array ...$arrays): array
When merging arrays, if multiple arrays have the same key names, the subsequent array value overwrites the value of the same key in the previous array.
Suppose we have two arrays: $array1 and $array2 , and we want to merge their differences, i.e. elements that exist in $array1 and not in $array2 . We can calculate the difference by array_diff_key() and then merge the difference using array_merge() .
Here is a sample code that demonstrates how to implement this function:
<?php
// Define two arrays
$array1 = [
'a' => 'apple',
'b' => 'banana',
'c' => 'cherry'
];
$array2 = [
'b' => 'blueberry',
'd' => 'date',
'e' => 'elderberry'
];
// use array_diff_key turn up array1 Unique keys
$diff = array_diff_key($array1, $array2);
// Merge the Differences
$result = array_merge($diff, $array2);
echo '<pre>';
print_r($result);
echo '</pre>';
?>
In this example, first we find the keys that exist in $array1 but not in $array2 (that is, the keys 'a' and 'c' ) through array_diff_key() . We then use array_merge() to merge these differences with $array2 . Finally, the merged array result is output.
After running the above code, the output results are as follows:
Array
(
[a] => apple
[c] => cherry
[b] => blueberry
[d] => date
[e] => elderberry
)
As you can see, 'a' => 'apple' and 'c' => 'cherry' in $array1 are preserved and the elements in $array2 are merged.
Assuming you need to include some URLs in the array and replace their domain names, we can simply use the str_replace() function to replace the domain name part in the URL during the merge process. For example:
