How to sort arrays from small to large in php

PHP is a widely used open source server-side scripting language that is commonly used in web development and can create dynamic pages, process form data, and file uploads. PHP not only supports operations on various data types, but also supports operations on various data structures, such as arrays.

Array is the most commonly used data structure in PHP. It can be used to store a set of data, including numbers, strings, and objects. In PHP, you can use the sort() function to sort an array. The sort() function can sort the array elements in order from small to large.

Sorting is a basic operation in data processing. It arranges a set of unordered data in a specific order to make the data more orderly and convenient for search, comparison and statistics. In PHP, you can use the sort() function to sort an array. This function can sort the array from small to large. The specific usage is as follows:

<?php $numbers = array(4, 2, 8, 6);
sort($numbers);
print_r($numbers);
?>

In the above code, $numbers is a For an array containing 4 numbers, the sort() function will sort it in ascending order, and the final output result will be [2, 4, 6, 8].

In addition to the sort() function, PHP also provides several other sorting functions, such as asort(), arsort(), ksort(), etc. Their functions and usage are similar to sort(). The difference is that the sorting method is slightly different. Let's take a look at the usage of these functions.

1. asort() function

asort() function can sort the array from small to large, but it will not change the relationship between key name and key value, that is, key value The relationship with the key name is still one-to-one correspondence.

<?php $age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
asort($age);
print_r($age);
?>

The output result is:

Array
(
    [Peter] => 35
    [Ben] => 37
    [Joe] => 43
) 

In the above example, $age is an associative array containing 3 elements. The asort() function will sort the elements in order from small to large. The values ​​are sorted, and the output result is [Peter=>35, Ben=>37, Joe=>43].

2. arsort() function

The arsort() function is similar to the asort() function. It can also sort the array from small to large, but the difference is that arsort() Functions preserve the relationship between key names and key values.

<?php $age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
arsort($age);
print_r($age);
?>

The output result is:

Array
(
    [Joe] => 43
    [Ben] => 37
    [Peter] => 35
)

In the above example, the arsort() function will sort the values ​​of the elements from small to large, but the difference between the key name and the key value Contacts are still one-to-one correspondence.

3. ksort() function

The ksort() function can sort the keys of the array from small to large.

<?php $age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
ksort($age);
print_r($age);
?>

The output result is:

Array
(
    [Ben] => 37
    [Joe] => 43
    [Peter] => 35
)

In the above example, the ksort() function will sort the keys of the array from small to large, and the output result is [Ben=> 37, Joe=>43, Peter=>35].

4. natsort() function

The natsort() function is a natural sorting function that can sort arrays according to natural sorting.

<?php $array1 = array("img12.png", "img10.png", "img2.png", "img1.png");
natsort($array1);
print_r($array1);
?>

The output result is:

Array
(
    [3] => img1.png
    [2] => img2.png
    [1] => img10.png
    [0] => img12.png
)

In the above example, the natsort() function will sort the array according to the natural sorting method, and the output result is [img1.png, img2.png , img10.png, img12.png].

To sum up, PHP provides a variety of functions for sorting arrays, and you can choose different functions for sorting according to actual needs. For situations where element values ​​need to be sorted, the sort(), asort(), and arsort() functions can be used; for situations where keys need to be sorted, the ksort() function can be used; and for situations where natural sorting is required, In the case of sorting, you can use the natsort() function.

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