Combining array_diff() with array_values() to rebuild index arrays

How to combine array_diff() and array_values() to realize the function of rebuilding indexes after deleting array elements?

In PHP, arrays are very commonly used data structures, and there are many functions for array operation. Among them, array_diff() and array_values() are two common array operation functions. array_diff() is used to calculate the difference between two arrays, while array_values() returns a reindexed array.

Sometimes, we need to delete some elements in the array and regenerate the index of the array after deleting the elements. This requirement is very common when dealing with arrays, especially when we delete certain specific values ​​from the array, we want to regenerate consecutive indexes. The following will demonstrate how to use array_diff() and array_values() in combination to achieve this function.

1. Introduction to the basic array_diff() function

The array_diff() function is used to calculate the difference between two or more arrays, returning an array of elements contained in the first array but not in other arrays.

For example:

 $array1 = [1, 2, 3, 4];
$array2 = [2, 4];

$result = array_diff($array1, $array2);
print_r($result);

Output:

 Array
(
    [0] => 1
    [2] => 3
)

In this example, array_diff() returns an array containing elements in array1 but not in array2 , and elements 2 and 4 are deleted.

2. How to rebuild index using array_values()

When we delete certain elements using array_diff() , the index of the resulting array may become discontinuous. To regenerate the index of the array, we can use array_values() . array_values() returns a new array with the index starting from 0 and rearranged the elements of the array.

For example:

 $array = [10 => 'a', 11 => 'b', 12 => 'c'];
$array = array_values($array);
print_r($array);

Output:

 Array
(
    [0] => a
    [1] => b
    [2] => c
)

3. Combining array_diff() and array_values() to delete and rebuild the index

Now, we can combine array_diff() and array_values() to implement the function of deleting array elements and rebuilding indexes. Suppose we have an array where we need to remove some specified elements from it and want the final array index to start again from 0 .

Sample code:

 // Original array
$array1 = [1, 2, 3, 4, 5, 6, 7];

// Delete the value as 2 and 4 Elements
$array2 = [2, 4];

$result = array_diff($array1, $array2);

// Reindex
$result = array_values($result);

print_r($result);

Output:

 Array
(
    [0] => 1
    [1] => 3
    [2] => 5
    [3] => 6
    [4] => 7
)

In this example, first we use array_diff() to delete elements with values ​​2 and 4 , and then reconstruct the index through array_values() so that the index of the result array starts from 0 , ensuring continuity.

4. Use scenarios

This method is very suitable for scenes where the array index is guaranteed to be contiguous after certain elements need to be removed from the array. For example, when you process user data, deleting certain unwanted items and re-indexes can avoid problems in subsequent operations.

Summarize

By combining array_diff() and array_values() , we can easily delete specific elements from the array and regenerate a continuous indexed array. This approach is very useful when dealing with complex array operations, simplifying code and increasing efficiency.