Is it possible to apply a sub range to an array in ruby like this:
> array = [4, 3, 2, 1]
> array[0...2]
=> [4, 3]
if the [0...2] is stored in a variable? I can't seem to get a syntax to give me what I want. What replaces the <?> in the following, if anything?
> array = [4, 3, 2, 1]
> range = [0...2]
> array<?>
=> [4, 3]
Yes, sure! Do this way:
array = [4, 3, 2, 1]
exclusive_range = [0...2] # Will get 0th and 1st element of the array
inclusive_range = [0..2] # Will get 0th, 1st and 2nd element of the array
array[exclusive_range.first]
# => [4, 3]
array[inclusive_range.first]
# => [4, 3, 2]
If you want to avoid .first call, you can put your range in a variable (Not in an array):
range = 0...2
array[range]
# => [4, 3]
0...2) is the first element of exclusive_range array.range.first. Let me know if you any other question.
range variable does not point to a Range object, it points to an Array object with a single element which is a Range object. Square brackets [] denote an Array literal. You could fix this by assigning a Range to the range variable instead of an Array of Ranges.Note that (0..2).size #=> 3. If you want to return [4,3] you want:
range = 0..1
You could use it like this:
array[range] #=> [4, 3]
or like this:
array.values_at *range #=> [4, 3]
