PHP knowledge points (1)-array functions

Pointer in array

 -current ()-key ()-prev ()-next ()-reset ()-end ()   pre-defined array  $_server () $_env () $_request () $_get () $_post () $_files$_session () $_cookie () $GLOBALS ()    key/value handling related functions for arrays  array  array_keys ($array [, Search_value [, BOOL]])     Specifies that the first parameter represents all the key values of the returned array, specifies the second argument, returns only the key for that value, and the third value is a Boolean value that indicates whether the type is dependent. Array  array_values ($array)     Get a new array, the original array remains the same  bool  in_array () key    array_ Search () bool  is_set () bool  array_key_exists ()  array  array_flip ()     Key-value Exchange array   Array_reverse ()     Reverse count () = sizeof () array_count_values () Array_unique ()         The recurring value ignores the following    callback function  array  array_filter () bool   Array_walk () array   Array_map ()   Sort  sort () Rsort () Asort () Arsort () Ksort () Krsort () Natsort () Natcasesort () Usort () Uasort () Uksort () Array_ Multisort ()   Split, merge, decompose, and splice arrays  array_slice () Array_splice () Array_combine () Array_merge () Array_intersect () Array_diff ()    arrays and data Structures   Array_push ()     into the stack Array_pop () array_unshift ()   Some other functions  array_rand () Shuffle () Array_sum () range ( )