如何从数组中删除相反的值? [英] How do I remove opposite values from an array?

问题描述

我遇到一个问题，我试图创建一个方向数组，每个方向都不是多余的.

I have a problem where I am trying to create an array of directions in which each direction is not redundant.

plan = ["NORTH", "SOUTH", "SOUTH", "EAST", "WEST", "NORTH", "WEST"]

如您所见，该计划中的大多数值都是多余的，您也可以简单地告诉此人去 .

As you can see most of the values in this plan are redundant and you may as well simply tell the person to go "WEST".

plan = ["NORTH", "WEST", "SOUTH", "EAST"]

我还希望上面的计划返回一个空数组.

I also want the plan above to return an empty array.

推荐答案

给出一系列方向:

plan = %w[NORTH SOUTH SOUTH EAST WEST NORTH WEST]
#=> ["NORTH", "SOUTH", "SOUTH", "EAST", "WEST", "NORTH", "WEST"]

我会将方向转换为 x 和 y 坐标:

I would translate the directions into x and y coordinates:

x, y = 0, 0

plan.each do |direction|
  case direction
  when 'NORTH' then y += 1
  when 'EAST'  then x += 1
  when 'SOUTH' then y -= 1
  when 'WEST'  then x -= 1
  end
end

'NORTH'递增 y ，'SOUTH'递减 y ，与'EAST相同'/'WEST'和 x .

'NORTH' increments y, 'SOUTH' decrements y, same for 'EAST' / 'WEST' and x.

使用示例数组可以得出:

With the example array this gives:

x #=> -1
y #=> 0

这些必须转换回方向数组:

These have to be translated back to an array of directions:

[
  *Array.new(y.abs) { y.positive? ? 'NORTH' : 'SOUTH' },
  *Array.new(x.abs) { x.positive? ? 'EAST' : 'WEST' }
]
#=> ["WEST"]

尽管这不是最短的代码，但是它相对容易掌握IMO.

Although this is not the shortest code, it's relatively easy to grasp IMO.

这篇关于如何从数组中删除相反的值?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！