key
Description
Syntax
key( array|object $array ): int|string|null
Parameters
array
The array.
Return
Returns the key of the array element that's currently being pointed to by the internal pointer.
It does not move the pointer in any way. If the internal pointer points beyond the end of the elements list or the array is empty, it returns null.
Examples
1 · current
<? $array = [ "a" => 0, "b" => 1, "c" => 2, "d" => 3, "e" => 4 ]; $return = key($array); echo $return;
a
2 · next
<? $array = [ "a" => 0, "b" => 1, "c" => 2, "d" => 3, "e" => 4 ]; next($array); $return = key($array); echo $return;
b
3 · for
<? $array = [ "a" => 0, "b" => 1, "c" => 2, "d" => 3, "e" => 4 ]; for($i = 0; $i < count($array); ++$i) { $return = key($array); echo $return; next($array); }
abcde
4 · foreach · value
<? $array = [ "a" => 0, "b" => 1, "c" => 2, "d" => 3, "e" => 4 ]; foreach($array as $value) { $return = key($array); echo $return; next($array); }
abcde
5 · foreach · key value
<? $array = [ "a" => 0, "b" => 1, "c" => 2, "d" => 3, "e" => 4 ]; foreach($array as $key => $value) { echo $key; }
abcde
6 · while
<? $array = [ "a" => 0, "b" => 1, "c" => 2, "d" => 3, "e" => 4 ]; $i = 0; while($i < count($array)) { $return = key($array); echo $return; next($array); ++$i; }
abcde
Links
Array
- array
- array_all
- array_any
- array_change_key_case
- array_chunk
- array_column
- array_combine
- array_count_values
- array_diff
- array_diff_assoc
- array_diff_key
- array_diff_uassoc
- array_diff_ukey
- array_fill
- array_fill_keys
- array_filter
- array_find
- array_find_key
- array_flip
- array_intersect
- array_intersect_assoc
- array_intersect_key
- array_intersect_uassoc
- array_intersect_ukey
- array_key_exists
- array_key_first
- array_key_last
- array_keys
- array_map
- array_merge
- array_merge_recursive
- array_multisort
- array_pad
- array_pop
- array_product
- array_push
- array_rand
- array_reduce
- array_replace
- array_replace_recursive
- array_reverse
- array_search
- array_shift
- array_slice
- array_splice
- array_sum
- array_udiff
- array_udiff_assoc
- array_udiff_uassoc
- array_uintersect
- array_uintersect_assoc
- array_uintersect_uassoc
- array_unique
- array_unshift
- array_values
- array_walk
- array_walk_recursive
- arsort
- asort
- compact
- count
- current
- end
- extract
- in_array
- key_exists
- krsort
- ksort
- list
- natcasesort
- natsort
- next
- pos
- prev
- range
- reset
- rsort
- shuffle
- sizeof
- sort
- uasort
- uksort
- usort