ruby-on-rails - 如何使用 sort_by 按字母顺序排序，然后按数字排序，然后按特殊字符排序

Question

我有一个数组:

arr = ["Bar", "abc", "foo", "1", "20”, "10", "_def"]

我需要先使用不区分大小写的字母顺序排序，然后是数字，然后是特殊字符。

我正在尝试使用 sort_by:

irb(main):071:0> arr.sort_by {|s| [s[/[0-9a-z]+/], s.to_i]}
=> ["1", "10", "20", "abc", "Bar", "_def", "foo"]

输出必须是:

arr = ["abc", "Bar", "foo", "1", “10”, “20", "_def"]

Answer 1

来自 docs :

Arrays are compared in an “element-wise” manner; the first element of ary is compared with the first one of other_ary using the <=> operator, then each of the second elements, etc…

您可以通过创建排序组来利用此行为:

arr = ["Bar", "abc", "foo", "1", "20", "10", "_def"]

arr.sort_by do |s|
  case s
  when /^[a-z]/i
    [1, s.downcase]
  when /^\d/
    [2, s.to_i]
  else
    [3, s]
  end
end
#=> ["abc", "Bar", "foo", "1", "10", "20", "_def"]

第一个元素(1、2、3)定义了组的位置:第一个位置是字母字符串，第二个位置是数字字符串，第三个位置是剩余的。在每个组中，元素按第二个元素排序:带字母的字符串按其小写值排序，数字字符串按其整数值排序，其余按自身排序。