I'm doing some koans exercises and am having trouble understanding the values returned with symbols inside arrays. Can someone explain why the following are equal or suggest a good article on the subject that I could infer the proper knowledge from??? This is different than with strings:
array = [:peanut, :butter, :and, :jelly]
assert_equal [:and, :jelly], array[2,2]
assert_equal [:and, :jelly], array[2,20]
assert_equal [:jelly, :peanut], array[4,0]
assert_equal [:jelly, :jelly], array[4,100]
Check out now and always documentation: ary[start, length] → new_ary or nil.
It returns subarray. Here 'start' is the index of first element in you array, length stands for length of subarray. If length >= ary.size - start you will get subarray from start to end of ary.
In your case:
array = [:peanut, :butter, :and, :jelly]
array[2, 2] #=> [:and, jelly]
array[2,20] #=> [:and, jelly]
array[4, 0] #=> []; length of empty array is 0!
array[4, 100] #=> []; well, okay. There's no element with index equal to 4.
# but holy documentation says "empty array is returned when
# the starting index for an element range is at the end of
# the array."
array[5, 0] #=> nil; there's nothing at 5th position.
array[-2, 2] #=> [:and, jelly]; :)
You told that strings inside arrays act not like this? You must be facing black magic. May you provide me an example?