The asort()function in PHP

The asort() function in PHP is used to sort an associative array in ascending order, according to the values, while maintaining the key association (i.e., keys are preserved).

Syntax:

  
asort(array &$array, int $flags = SORT_REGULAR): bool  

• &$array: The input array (passed by reference and modified in place)
• flags: Optional. Specifies the sorting behavior. Common flags:
  • SORT_REGULAR – Default: Compare items normally
  • SORT_NUMERIC – Compare items numerically
  • SORT_STRING – Compare items as strings
  • SORT_NATURAL – Compare items using "natural order" (like natsort)

Example 1: Basic Usage

  
$fruits = array("a" => "banana", "b" => "apple", "c" => "mango");  
asort($fruits);  
  
print_r($fruits);  

Output:

  
Array  
(  
    [b] => apple  
    [a] => banana  
    [c] => mango  
)  

Values are sorted, but the keys (a, b, c) remain associated with their original values.

Example 2: Numeric Array

  
$numbers = array("x" => 40, "y" => 10, "z" => 100);  
asort($numbers);  
  
print_r($numbers);  

Output:

  
Array  
(  
    [y] => 10  
    [x] => 40  
    [z] => 100  
)  

Sorted by values in ascending order, keys preserved.

Example 3: With SORT_STRING

  
$data = array("x" => "20", "y" => "100", "z" => "3");  
asort($data, SORT_STRING);  
  
print_r($data);  

Output:

  
Array  
(  
    [y] => 100  
    [x] => 20  
    [z] => 3  
)  

String-based sorting: "100" comes before "20" and "3".

Related Functions:

• arsort() – Sort by values in descending order, maintain keys
• ksort() – Sort by keys in ascending order
• krsort() – Sort by keys in descending order
• sort() – Sort by values, reset keys (numeric array)
• usort() – User-defined sort by values