php array short division

In PHP programming, array is a very important data structure. In array processing, we often encounter the need to delete specified elements. Normally, we will choose to use the unset keyword to delete the specified array element, but sometimes we need to perform a simpler way, which is the so-called "short division".

Short division, as the name suggests, refers to a simple and efficient array deletion method. Different from the cumbersome use of the unset function, short division allows us to complete the deletion of array elements in one line of code. So, what exactly is short division? How is it achieved?

1. The definition of short division

In layman's terms, short division is a technique to delete an element by copying a part of an array.

To put it simply, short division is to copy the array elements before and after the element that needs to be deleted to another array to achieve the purpose of "deleting" the element.

2. Implementation of short division

The implementation of short division is very simple. We can implement it through the following code:

$del_index = 1; //Under the element that needs to be deleted Standard
$new_array = array_merge(array_slice($array, 0, $del_index),array_slice($array, $del_index 1));

Among them, $array is the original array and $del_index needs to be deleted The subscript of the element, $new_array is the new array after deleting the specified element.

In the above code, we use the array_slice() function to perform array cutting. The first parameter is the array that needs to be cut, and the second parameter is the starting index that needs to be cut. The three parameters are the length to be cut. In the above code, we cut twice and merge the arrays into a new array through the array_merge() function.

3. Advantages of short division

Compared with using unset to delete elements, short division has the following three advantages:

1. Simple and easy to understand. Using short division, you only need one line of code to complete the operation of deleting elements, without using the unset function to delete, so short division is simpler and easier to understand.

2. High efficiency. Using short division, you can operate directly on the original array, reducing unnecessary operations, so it is more efficient than other methods.

3. Keep the original array. Using short division, you can actually retain the original array, but through the cutting operation, some elements of the original array are "invisible". For the needs of change operations, the original array can be retained.

4. Restrictions on the use of short division

The prerequisite for using short division is that the following two conditions must be met:

1. The subscript of the array is a non-negative integer. And non-consecutive subscripts. That is, the array is an indexed array and there is no deletion of duplicate elements.

2. It is applicable when the array is small. If the array is large, it is not recommended because copying the array will cause additional memory overhead and is not conducive to the performance of the program.

5. Summary

Short division is a very simple and efficient method of deleting array elements, and is suitable for small-scale array deletion operations. Using short division can retain the original array, save operation code, and improve program efficiency. Compared with using unset to delete elements, short division is more convenient and faster, and it is a trick well known to PHP programmers.

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