重复一个序列，并用一个数组进行交织

I have an array like this:

我有一个这样的数组:

array = ['1','a','2','b']

I want to make it like this:

我想这样做:

['x', '1', 'y', 'a', 'x', '2', 'y', 'b']

I tried for many hours but has no result. My best attempt was:

我试了好几个小时，但没有结果。我最好的意图是:

a = array.each_with_index do |val, index|
  case index
  when index == 0
    a.insert(index, 'x')
  when index.odd?
    a.insert(index, 'x')
  when index.even?
    a.insert(index, 'y')
  end
end

3 个解决方案

#1

You could do something like this, using methods from the Enumerable module:

您可以使用可枚举模块中的方法来做类似的事情:

ary = ['1', 'a', '2', 'b']
xy = ['x', 'y']

ary.zip(xy.cycle)
# => [["1", "x"], ["a", "y"], ["2", "x"], ["b", "y"]]

ary.zip(xy.cycle).flat_map(&:reverse)
# => ["x", "1", "y", "a", "x", "2", "y", "b"]

#2

Also any of these ways will work

而且，这些方法中的任何一种都会起作用

array = ['1','a','2','b']

array.each_slice(2).map {|a| ['x','y'].zip(a)}.flatten.compact
#=>["x", "1", "y", "a", "x", "2", "y", "b"]

(['x','y'] * (array.size / 2.0).ceil).take(array.size).zip(array).flatten
#=>["x", "1", "y", "a", "x", "2", "y", "b"]

array.each_slice(2).flat_map {|a| ['x','y'].zip(a).flatten}.compact
#=>["x", "1", "y", "a", "x", "2", "y", "b"]

['x','y'].cycle(array.size / 2 + array.size % 2).take(array.size).zip(array).flatten
#=>["x", "1", "y", "a", "x", "2", "y", "b"]

#3

This might help:

这可能帮助:

array.zip(['x', 'y'].cycle).map(&:reverse).flatten(1) #=> ["x", "1", "y", "a", "x", "2", "y", "b"]

#1