How to remove array elements in php

In PHP, we often need to perform some operations on arrays, such as adding, deleting, filtering, etc. Among them, deleting elements in an array is one of the more common operations. This article will introduce several methods of removing array elements in PHP and discuss their advantages and disadvantages.

1. Use the unset() function

Use the unset() function to delete the specified element in the array. The syntax is as follows:

unset($array[key]) ;

Among them, $array is the array of elements to be deleted, and key is the key name of the element to be deleted. An example of using the unset() function to delete elements is as follows:

// Create an associative array
$person = array('name' => 'Tom', 'age ' => 20, 'gender' => 'male');

//Delete the 'age' element in the associative array
unset($person['age']);

// Output variable $person
print_r($person);
?>

The output result is as follows:

Array
(

[name] => Tom
[gender] => male

)

2. Use the array_diff() function

Use the array_diff() function to compare the elements of two or more arrays and return the difference. If we want to delete certain elements in the array, we can pass the elements to be deleted as an array to the array_diff() function, and then reassign the returned result to the original array.

The following is a sample code:

// Create an array
$fruit = array('apple', 'banana', 'cherry', 'durian');

//The element to be deleted
$toRemove = array('banana', 'cherry');

//The element to be deleted will be the second Parameters are passed to the array_diff() function
$fruit = array_diff($fruit, $toRemove);

// Output array $fruit
print_r($fruit);
?>

The output result is as follows:

Array
(

[0] => apple
[3] => durian

)

3. Use array_filter() function

Use array_filter( ) function can filter elements in the array, and it can accept a custom callback function as a filter condition. This callback function accepts each element in the array as input and returns a Boolean value. If the return value is true, the element is saved, otherwise the element is deleted.

The following is a sample code:

// Create an array
$numbers = array(1, 2, 3, 4, 5, 6) ;

// Define a callback function to save all elements greater than 3
function filterNumbers($value)
{

return ($value > 3);</p>
<p>}</p>
<p>// Use The array_filter() function filters the elements in the array<br>$numbers = array_filter($numbers, 'filterNumbers');</p>
<p>// Output array $numbers<br>print_r($numbers);<br>? ></p>
<p>The output result is as follows:</p>
<p>Array<br>(</p>
<pre class="brush:php;toolbar:false">[3] => 4
[4] => 5
[5] => 6

)

4. Use the array_splice() function

Use the array_splice() function to delete elements from an array and return the deleted elements. This function can accept one or more index parameters, indicating the position of the element to be deleted in the array.

The following is a sample code:

// Create an array
$alphabet = array('a', 'b', 'c', 'd', 'e', ​​'f');

// Use the array_splice() function to delete the second and third elements in the array
$removed = array_splice($alphabet, 1 , 2);

//Output array $alphabet and deleted elements $removed
print_r($alphabet);
print_r($removed);
?>

The output results are as follows:

Array
(

[0] => a
[1] => d
[2] => e
[3] => f

)
Array
(

[0] => b
[1] => c

)

5. Use array_pop() and array_shift() functions

Use the array_pop() function to delete the last element in the array, and use the array_shift() function to delete the first element in the array.

The following is a sample code:

// Create an array
$content = array('header', 'body', 'footer') ;

//Delete the last element in the array
array_pop($content);

//Delete the first element in the array
array_shift($content);

// Output array $content
print_r($content);
?>

The output result is as follows:

Array
(

[0] => body

)

The above are several ways to remove array elements in PHP. Using these methods can help us better manage and operate PHP arrays. Please choose the method that suits you according to your actual needs to avoid unnecessary trouble.

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