arrays - 当该范围是变量时，ruby 数组子范围

Question

是否可以像这样将子范围应用于 ruby​​ 中的数组:

 > array = [4, 3, 2, 1]
 > array[0...2]
=> [4, 3]

如果[0...2]存储在变量中？我似乎无法获得语法来满足我的需求。什么取代了 <?>在下面，如果有的话？

 > array = [4, 3, 2, 1]
 > range = [0...2]
 > array<?>
=> [4, 3]

Answer 1

是的，当然!这样做:

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]

如果你想避免 .first 调用，你可以将你的范围放在一个变量中(而不是在一个数组中):

range = 0...2
array[range]
# => [4, 3]