(PHP 4, PHP 5, PHP 7)
sort — Sort an array
&$array
   [, int $sort_flags = SORT_REGULAR
  ] )This function sorts an array. Elements will be arranged from lowest to highest when this function has completed.
arrayThe input array.
sort_flags
       The optional second parameter sort_flags
       may be used to modify the sorting behavior using these values:
      
Sorting type flags:
SORT_REGULAR - compare items normally
         (don't change types)
        SORT_NUMERIC - compare items numerically
        SORT_STRING - compare items as strings
        SORT_LOCALE_STRING - compare items as
          strings, based on the current locale. It uses the locale,
          which can be changed using setlocale()
         
        SORT_NATURAL - compare items as strings
          using "natural ordering" like natsort()
         
        SORT_FLAG_CASE - can be combined
          (bitwise OR) with
          SORT_STRING or
          SORT_NATURAL to sort strings case-insensitively
         
        
   Returns TRUE on success or FALSE on failure.
  
| Version | Description | 
|---|---|
| 5.4.0 | Added support for SORT_NATURALandSORT_FLAG_CASEassort_flags | 
| 5.0.2 | Added SORT_LOCALE_STRING | 
Example #1 sort() example
<?php
$fruits = array("lemon", "orange", "banana", "apple");
sort($fruits);
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "\n";
}
?>
The above example will output:
fruits[0] = apple fruits[1] = banana fruits[2] = lemon fruits[3] = orange
The fruits have been sorted in alphabetical order.
Example #2 sort() example using case-insensitive natural ordering
<?php
$fruits = array(
    "Orange1", "orange2", "Orange3", "orange20"
);
sort($fruits, SORT_NATURAL | SORT_FLAG_CASE);
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "\n";
}
?>
The above example will output:
fruits[0] = Orange1 fruits[1] = orange2 fruits[2] = Orange3 fruits[3] = orange20
The fruits have been sorted like natcasesort().
Note: This function assigns new keys to the elements in
array. It will remove any existing keys that may have been assigned, rather than just reordering the keys.
Note: Like most PHP sorting functions, sort() uses an implementation of » Quicksort. The pivot is chosen in the middle of the partition resulting in an optimal time for already sorted arrays. This is however an implementation detail you shouldn't rely on.
Be careful when sorting arrays with mixed types values because sort() can produce unpredictable results.