How to delete specified items in an array in php

In the process of developing using PHP language, it is often necessary to delete arrays. However, the array deletion function provided by PHP has limitations and may not meet our needs. In this case, we can use the powerful programming features of PHP to implement our own delete function to better meet business needs.

This article will introduce how to use PHP to write your own array deletion function and give some example codes. We will discuss the following:

• Basic knowledge of PHP array deletion operations

• Delete the specified array item through the unset() function

• Delete the specified array item through the array_splice() function

• Delete the specified array item through the array_diff() function

1. Basic knowledge of PHP array deletion operations

In PHP, we can use arrays to store data. However, the elements in an array are ordered, and each element has a unique index value. Normally, we use index values ​​to access elements in an array. For example, if we want to access the first element of an array named "test" we would use the following code:

$array = array('apple', 'banana', 'cherry');
echo $array[0];

This will output "apple" because "apple" is the first in the array element.

Deleting array elements is a common operation. PHP provides some built-in functions to delete elements from an array. In the following chapters, we will introduce how to use these functions.

2. Delete the specified item in the array through the unset() function

PHP’s unset() function can delete the specified element in the array. This function accepts one or more parameters, each parameter is the index value of the array element to be deleted. Here is an example:

$array = array('apple', 'banana', 'cherry');
unset($array[1]); //删除数组中的第二个元素
print_r($array);

This code will output the following results:

Array
(
    [0] => apple
    [2] => cherry
)

In this example, the unset() function is used to delete the second element "banana" in the array. Since the array part shrinks "vertically", the index value of "apple" becomes 0 and the index value of "cherry" becomes 1.

3. Delete the specified array item through the array_splice() function

PHP’s array_splice() function can delete the specified element from the array and replace it with Replaced with other elements. The first parameter of this function is the array to be operated on, the second parameter is the starting index of the element to be deleted, the third parameter is the number of elements to be deleted, and the fourth parameter is the element to be inserted into the array. Here is an example:

$array = array('apple', 'banana', 'cherry');
array_splice($array, 1, 1); //删除数组中的第二个元素
print_r($array);

This code will output the following results:

Array
(
    [0] => apple
    [1] => cherry
)

In this example, the array_splice() function removes the second element "banana" from the array and replaces it with Other elements move upward. Since we don't provide an element to insert, no replacement will occur in the array.

4. Delete the specified item in the array through the array_diff() function

PHP’s array_diff() function can delete the specified element in the array. This function accepts any number of arguments, each of which is an element to be removed from the array. Here is an example:

$array = array('apple', 'banana', 'cherry');
$array = array_diff($array, array('banana')); //删除数组中的第二个元素
print_r($array);

The code will output the following results:

Array
(
    [0] => apple
    [1] => cherry
)

In this example, the array_diff() function compares the elements of two arrays and returns a unique set of elements. The first array we pass contains the elements to be removed, while the second array is the original array. The function returns a new array containing the elements from the original array that were not deleted.

Conclusion:

Deleting array elements in PHP is very simple, and there are many methods to choose from. Basically the easiest way is if you use PHP's unset() function to remove array elements. If you need to preserve the array size when removing elements, you can use the array_splice() function. Finally, if you already have a list of elements to remove, you can use the array_diff() function to quickly remove elements.

Okay, the above is an introduction to deleting specified items in an array in PHP. I hope it will be helpful to everyone!

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