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English
In PHP, array_diff_assoc() is a commonly used function that compares two arrays and returns the difference between them. This function not only compares the values of the array, but also compares the key names of the array. Therefore, many developers will have a question when using it: if we ignore the key names when comparing arrays, can we achieve the expected results?
This article will use some examples to explore whether ignoring the key name when using array_diff_assoc() can actually achieve the expected result.
First of all, it is very important to understand the basic usage of array_diff_assoc() . This function compares the keys and values of two arrays, and it returns an array containing the differential values. It should be noted that array_diff_assoc() checks the equality of key names and values, so it is not just about comparing values.
<?php
$array1 = array("a" => "apple", "b" => "banana", "c" => "cherry");
$array2 = array("a" => "apple", "b" => "blueberry", "d" => "date");
$result = array_diff_assoc($array1, $array2);
print_r($result);
?>
Array
(
[b] => banana
[c] => cherry
)
In this example, array_diff_assoc() compares the key names and values of the two arrays and returns items that are in array array1 but not in array2 .
Sometimes, developers want to compare their values without considering the key names in the array when comparing. In this case, array_diff_assoc() does not satisfy the requirement because it compares the key names and values at the same time. If you want to ignore the key names and compare only the values, you should use array_diff() .
Suppose we have two arrays with different key names but the same values:
<?php
$array1 = array("a" => "apple", "b" => "banana", "c" => "cherry");
$array2 = array("x" => "apple", "y" => "banana", "z" => "cherry");
$result = array_diff($array1, $array2);
print_r($result);
?>
Array
(
)
The array_diff() function is used here, and the result is an empty array, because array_diff() only compares the values of the array, and array array1 and array2 contain the same values. Unlike array_diff_assoc() , array_diff() does not take into account the key name, so it ignores the difference in key name and gets the expected result.
As can be seen from the example above, array_diff_assoc() is not the most suitable choice if we want to ignore the key names and compare only the values of the array. On the contrary, array_diff() is the right tool to implement this function. array_diff_assoc() is still very useful when it is necessary to consider both the key name and the value difference, but if you only care about the difference in the value and ignore the key name, it will be more appropriate to use array_diff() .
To sum up, array_diff_assoc() cannot ignore the key name, so when you need to ignore the key name, you should choose array_diff() instead of array_diff_assoc() .
