The constants below are always available as part of the PHP core.
CASE_LOWER
(int) CASE_LOWER
is used with array_change_key_case() and is used to convert array keys to lower case. This is also the default case for array_change_key_case(). As of PHP 8.2.0, only ASCII characters will be converted. CASE_UPPER
(int) CASE_UPPER
is used with array_change_key_case() and is used to convert array keys to upper case. As of PHP 8.2.0, only ASCII characters will be converted. Sorting order flags:
SORT_ASC
(int) SORT_ASC
is used with array_multisort() to sort in ascending order. SORT_DESC
(int) SORT_DESC
is used with array_multisort() to sort in descending order. Sorting type flags: used by various sort functions
SORT_REGULAR
(int) SORT_REGULAR
is used to compare items normally. SORT_NUMERIC
(int) SORT_NUMERIC
is used to compare items numerically. SORT_STRING
(int) SORT_STRING
is used to compare items as strings. SORT_LOCALE_STRING
(int) SORT_LOCALE_STRING
is used to compare items as strings, based on the current locale. SORT_NATURAL
(int) SORT_NATURAL
is used to compare items as strings using "natural ordering" like natsort(). SORT_FLAG_CASE
(int) SORT_FLAG_CASE
can be combined (bitwise OR) with SORT_STRING
or SORT_NATURAL
to sort strings case-insensitively. As of PHP 8.2.0, only ASCII case folding will be done. Filter flags:
ARRAY_FILTER_USE_KEY
(int) ARRAY_FILTER_USE_KEY
is used with array_filter() to pass each key as the first argument to the given callback function. ARRAY_FILTER_USE_BOTH
(int) ARRAY_FILTER_USE_BOTH
is used with array_filter() to pass both value and key to the given callback function.