How to remove elements from an array in php

In PHP, array is a very important and powerful data type, which allows developers to store and manipulate data easily. PHP provides many built-in functions so that we can add, delete, sort, and other operations on arrays. This article will focus on how to remove elements from an array.

1. unset function

In PHP, you can use the unset function to remove elements at a specified position in an array. The unset function can accept one or more parameters, each parameter is the subscript of the element to be deleted in an array.

The following is an example of using the unset function to remove array elements:

$arr = array('apple', 'banana', 'orange', 'peach');
unset($arr[1]); // 移除索引为1的元素，即 'banana'
print_r($arr); // 输出：Array ( [0] => apple [2] => orange [3] => peach )

In the above code, we use the unset function to remove the element with index 1 in the array, which is 'banana'. Then use the print_r function to print out the array after deleting the elements. You can see that 'banana' is no longer in the array.

2. array_splice function

In addition to using the unset function, you can also use the array_splice function to remove the array. The array_splice function can delete an element in the array and insert new elements at the same time.

The syntax of the array_splice function is as follows:

array_splice(array &$input, int $offset, int $length = 0, mixed $replacement = []);

Parameter analysis:

• $input: Reference to the target array.
• $offset: The offset of the starting position. If it is a negative number, it means starting from the end of the array.
• $length: The number of elements to be deleted. Default is 0.
• $replacement: The element to be inserted into the array. Default is empty.

The following is an example of using the array_splice function to remove array elements:

$arr = array('apple', 'banana', 'orange', 'peach');
array_splice($arr, 1, 1); // 移除索引为1的元素，即 'banana'
print_r($arr); // 输出：Array ( [0] => apple [1] => orange [2] => peach )

In the above code, we use the array_splice function to remove the element with index 1 in the array, that is, ' banana'. You can see that the deleted array elements have been rearranged.

3. array_diff function

In addition to the above two methods, you can also use the array_diff function to remove elements from an array. The array_diff function is used to calculate the difference set of arrays and compare the differences between multiple arrays.

The syntax of the array_diff function is as follows:

array_diff(array $array1, array ...$arrays): array

Parameter analysis:

• $array1: The first array to be compared.
• $arrays: Can be one or more arrays, used to compare with the first array.

The following is an example of using the array_diff function to remove array elements:

$arr = array('apple', 'banana', 'orange', 'peach');
$res = array_diff($arr, array('banana')); // 移除 'banana' 元素
print_r($res); // 输出：Array ( [0] => apple [2] => orange [3] => peach )

In the above code, we use the array_diff function to remove the 'banana' element in the array. As you can see, the final result is to return a new array after deletion.

Summary

In this article we introduced 3 methods to remove elements from PHP arrays, namely: using the unset function, array_splice function and array_diff function. In actual development, we can choose different methods according to different scenarios to complete array operations more conveniently.

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