php - How to extract certain values from an array -

example here http://php.net/manual/en/function.array-slice.php

$input = array("a", "b", "c", "d", "e"); $output = array_slice($input, 2);      // returns "c", "d", , "e" $output = array_slice($input, -2, 1);  // returns "d" $output = array_slice($input, 0, 3);   // returns "a", "b", , "c" 

but how example "a", "d", , "e"?

like

$output = array_slice($input, 0, 1); $output = array_slice($input, 3, 1); $output = array_slice($input, -1, 1); 

but in 1 variable. possible?

update. want use 1st, 3rd , last element of array. if extract 1st, 3rd , last element , create new array 3 elements.

you have throw array_merge() mix, because array_slice() can extract subsequence of array, not arbitrary number of elements spread on entire array. extract each subsequence separately , merge them 1 array:

$slice1 = array_slice($input, 0, 1); $slice2 = array_slice($input, -2, 2); $output = array_merge($slice1, $slice2); 

be aware however, work, if know each element in array. in case, use direct array access, generate less overhead , easier read:

$output = array($input[0], $input[3], $input[4]); 

it might more reasonable use array_filter() or custom iterator. haven't provided enough information task that.

edit:
if it's matter of notation, try specifying array relevant indexes, switch around using array_fill_keys() in order use array_intersect_key() extract relevant elements array:

$indexes = array(0, 3, 4); $indexarray = array_fill_keys($indexes, true); $output = array_intersect_key($input, $indexarray);