PHP_array

array의 길이는 array_length가 아니라 sizeof를 사용.

php는 array에 associative_array (key-value pair; curr see 해시,hash) 기능을 모두 넣??? 다음 함수가 있음
array_push
array_pop
array_shift
array_unshift
array_pad - resize.
array_walk
array_reverse
array_flip
array_merge
array_slice
array_splice
shuffle

reset - rewind the internal pointer of the array back to the 1st element
end - moves the pointer to the last position of the array
each
next
prev
count
array_count_values
sort
rsort - reverse order sort.
asort - "array indexes maintain their original association with the elements regardless of the new position the element assumes" ???
arsort
ksort - key에 따라
krsort
usort - based on your own predefined criteria
uasort
uksort