Sort array by value php


The elements in an array can be sorted in alphabetical or numerical order, descending or ascending.


PHP - Sort Functions For Arrays

In this chapter, we will go through the following PHP array sort functions:

  • sort() - sort arrays in ascending order
  • rsort() - sort arrays in descending order
  • asort() - sort associative arrays in ascending order, according to the value
  • ksort() - sort associative arrays in ascending order, according to the key
  • arsort() - sort associative arrays in descending order, according to the value
  • krsort() - sort associative arrays in descending order, according to the key

Sort Array in Ascending Order - sort()

The following example sorts the elements of the $cars array in ascending alphabetical order:

Example

<?php
$cars = array("Volvo", "BMW", "Toyota");
sort($cars);
?>

Try it Yourself »

The following example sorts the elements of the $numbers array in ascending numerical order:



Sort Array in Descending Order - rsort()

The following example sorts the elements of the $cars array in descending alphabetical order:

Example

<?php
$cars = array("Volvo", "BMW", "Toyota");
rsort($cars);
?>

Try it Yourself »

The following example sorts the elements of the $numbers array in descending numerical order:


Sort Array (Ascending Order), According to Value - asort()

The following example sorts an associative array in ascending order, according to the value:

Example

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

Try it Yourself »


Sort Array (Ascending Order), According to Key - ksort()

The following example sorts an associative array in ascending order, according to the key:

Example

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

Try it Yourself »


Sort Array (Descending Order), According to Value - arsort()

The following example sorts an associative array in descending order, according to the value:

Example

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

Try it Yourself »


Sort Array (Descending Order), According to Key - krsort()

The following example sorts an associative array in descending order, according to the key:

Example

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

Try it Yourself »


Complete PHP Array Reference

For a complete reference of all array functions, go to our complete PHP Array Reference.

The reference contains a brief description, and examples of use, for each function!


PHP Exercises



PHP has several functions that deal with sorting arrays, and this document exists to help sort it all out.

The main differences are:

  • Some sort based on the array keys, whereas others by the values: $array['key'] = 'value';
  • Whether or not the correlation between the keys and values are maintained after the sort, which may mean the keys are reset numerically (0,1,2 ...)
  • The order of the sort: alphabetical, ascending (low to high), descending (high to low), natural, random, or user defined
  • Note: All of these sort functions act directly on the array variable itself, as opposed to returning a new sorted array
  • If any of these sort functions evaluates two members as equal then they retain their original order. Prior to PHP 8.0.0, their order were undefined (the sorting was not stable).
Sorting function attributes
Function nameSorts byMaintains key associationOrder of sortRelated functions
array_multisort() value string keys yes, int keys no first array or sort options array_walk()
asort() value yes ascending arsort()
arsort() value yes descending asort()
krsort() key yes descending ksort()
ksort() key yes ascending krsort()
natcasesort() value yes natural, case insensitive natsort()
natsort() value yes natural natcasesort()
rsort() value no descending sort()
shuffle() value no random array_rand()
sort() value no ascending rsort()
uasort() value yes user defined uksort()
uksort() key yes user defined uasort()
usort() value no user defined uasort()

&#34;Matthew Rice&#34;

9 years ago

While this may seem obvious, user-defined array sorting functions ( uksort(), uasort(), usort() ) will *not* be called if the array does not have *at least two values in it*.

The following code:

<?phpfunction usortTest($a, $b) {
   
var_dump($a);
   
var_dump($b);
    return -
1;
}
$test = array('val1');
usort($test, "usortTest");$test2 = array('val2', 'val3');
usort($test2, "usortTest");?>

Will output:

string(4) "val3"
string(4) "val2"

The first array doesn't get sent to the function.

Please, under no circumstance, place any logic that modifies values, or applies non-sorting business logic in these functions as they will not always be executed.

oculiz at gmail dot com

11 years ago

Another way to do a case case-insensitive sort by key would simply be:

<?php
uksort
($array, 'strcasecmp');
?>

Since strcasecmp is already predefined in php it saves you the trouble to actually write the comparison function yourself.

Hayley Watson

5 years ago

Stabilizing the sort functions (in this case, usort).

<?php
function stable_usort(&$array, $cmp)
{
   
$i = 0;
   
$array = array_map(function($elt)use(&$i)
    {
        return [
$i++, $elt];
    },
$array);
   
usort($array, function($a, $b)use($cmp)
    {
        return
$cmp($a[1], $b[1]) ?: ($a[0] - $b[0]);
    });
   
$array = array_column($array, 1);
}
?>

Tags each array element with its original position in the array so that when the comparison function returns 0 the tie can be broken to put the earlier element first.

How do you sort an array by a specific value in PHP?

PHP Sorting Arrays.
sort() - sort arrays in ascending order..
rsort() - sort arrays in descending order..
asort() - sort associative arrays in ascending order, according to the value..
ksort() - sort associative arrays in ascending order, according to the key..

How do you sort a value in an array?

Array.prototype.sort() The sort() method sorts the elements of an array in place and returns the reference to the same array, now sorted.

What is Asort () and arsort ()?

Definition and Usage The arsort() function sorts an associative array in descending order, according to the value. Tip: Use the asort() function to sort an associative array in ascending order, according to the value. Tip: Use the krsort() function to sort an associative array in descending order, according to the key.

What does sort () do in PHP?

Definition and Usage. The sort() function sorts an indexed array in ascending order. Tip: Use the rsort() function to sort an indexed array in descending order.

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