PHP 4, PHP 5, PHP 7, PHP 8
ksort - Sort an array by key in ascending order

ksort( arrayarray, [int$flags = SORT_REGULAR] ): bool

Sorts array in place by keys in ascending order.


If two members compare as equal, they retain their original order. Prior to PHP 8.0.0, their relative order in the sorted array was undefined.


Resets array's internal pointer to the first element.



The input array.


The optional second parameter flags may be used to modify the sorting behavior using these values:

Sorting type flags:

SORT_REGULAR - compare items normally; the details are described in the comparison operators section

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

Return Values

Always returns true.

Related Functions

Example of ksort

Show all examples for ksort

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