Ruby Array＃转置真实世界的例子

Question

有没有人有一个真实世界的例子，说明Array＃transpose会有用吗？我正在努力将功能与可能的应用程序联系起来。

Answer 1

如果你有一组名字可能会有用。第一个元素可能是名字，第二个元素可能是姓氏。

您可能想要获取名字或姓氏的列表

names = [["John", "Smith"],["Roger", "Jones"]]

您可以致电names.transpose.first

获取名字

Answer 2

考虑以下示例：

class Array
  def mean
    reduce(:+) / length
  end
end

locations = [
  [41.311000, -96.138319],
  [41.311355, -96.130380],
  [41.315319, -96.138319],
  [41.316093, -96.129994],
  [41.317640, -96.124372],
  [41.315964, -96.121883],
  [41.313128, -96.121968],
  [41.313160, -96.125101],
  [41.309775, -96.125316]
]

latitudes, longitudes = locations.transpose

puts latitudes.inspect
# => [41.311, 41.311355, 41.315319, 41.316093, ...

puts longitudes.inspect
# => [-96.138319, -96.13038, -96.138319, -96.129994 ...

weighted_center = [latitudes.mean, longitudes.mean]

puts weighted_center.inspect
# => [41.31371488888889, -96.12840577777779]

transpose可以被认为是zip

的反面