PHP array comparison to remove different values

In PHP programming, data comparison and deduplication issues are often involved. Among them, array comparison to remove different values ​​is a common problem, and it is also a difficult problem that many developers need to solve.

Why do we need to perform array comparison to operate on different values? Many times it is because we need to obtain data from different data sources and then integrate and process it. At this time, we need to perform array comparison operations to filter and deduplicate the data of different targets, and finally generate the target data we need.

So, how to perform array comparison to operate on different values? The following will introduce this problem in two common ways: using the in_array function and using the array_diff function.

Method 1: Use the in_array function for array comparison

In PHP, the in_array function can be used to determine whether an element exists in an array. Therefore, we can achieve the operation of array comparison to remove different values ​​by traversing and judging the array.

The specific implementation steps are as follows:

1. Define two arrays $arr1 and $arr2 to respectively store the two arrays that need to be compared.

2. Traverse the $arr1 array and use the in_array function to determine whether each element in the $arr1 array also exists in the $arr2 array.

3. If an element in the $arr1 array does not exist in the $arr2 array, add the element to a new array $result.

4. Traverse the $arr2 array and use the in_array function to determine whether each element in the $arr2 array also exists in the $arr1 array.

5. If an element in the $arr2 array does not exist in the $arr1 array, add the element to the $result array.

6. Return the $result array as the result we need.

The complete code implementation is as follows:

$arr1 = array("apple", "banana", "orange", "kiwi");
$arr2 = array("apple", "grape", "watermelon", "kiwi");
$result = array();

foreach ($arr1 as $value) {
    if(!in_array($value, $arr2)){
        array_push($result, $value);
    }
}

foreach ($arr2 as $value) {
    if(!in_array($value, $arr1)){
        array_push($result, $value);
    }
}

print_r($result);

The output result of the above code is:

Array
(
    [0] => banana
    [1] => orange
    [2] => grape
    [3] => watermelon
)

It can be seen that different elements in the array have been filtered out and successfully implemented Performs array comparison operations to remove different values.

It should be noted that using the in_array function to compare arrays to remove different values ​​requires two traversals. When there are many array elements, it will affect program performance and efficiency, so it is not suitable for applications with high performance requirements. Scenes.

Method 2: Use the array_diff function to compare arrays

Another common method is to use the array_diff function to compare arrays to remove different values. The array_diff function is used to find the difference set of multiple arrays. It can filter out different elements in multiple arrays, thereby realizing the operation of comparing arrays to remove different values.

The specific implementation steps are as follows:

1. Define two arrays $arr1 and $arr2, respectively storing the two arrays that need to be compared.
2. Use the array_diff function to compare different elements between the $arr1 and $arr2 arrays, respectively, and save the results to new arrays $result1 and $result2.
3. Merge the $result1 and $result2 arrays into a new array $result.
4. Return the $result array as the result we need.

The complete code implementation is as follows:

$arr1 = array("apple", "banana", "orange", "kiwi");
$arr2 = array("apple", "grape", "watermelon", "kiwi");
$result1 = array_diff($arr1, $arr2);
$result2 = array_diff($arr2, $arr1);
$result = array_merge($result1, $result2);
print_r($result);

The output result of the above code is:

Array
(
    [1] => banana
    [2] => orange
    [3] => grape
    [4] => watermelon
)

It can be seen that array comparison can also be successfully achieved using the array_diff function The operation of removing different values ​​requires only one traversal at the same time, which is more efficient and suitable for scenarios with high performance requirements.

Conclusion:

The operation of array comparison to remove different values ​​in PHP can be achieved by using the in_array function and array_diff function. The in_array function is suitable for smaller arrays and is not suitable for scenarios with high performance requirements; the array_diff function is suitable for all scenarios and has higher efficiency and performance advantages, and can be considered for use in actual programming.

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