有没有一种更惯用的方式来表达循环中还有多少迭代

Question

我正在写一个Ruby循环，如下所示：

iterations = 10
until iterations == 0
    unless iterations == 1
      puts "#{iterations} iterations until done"
    else
      puts "#{iterations} iteration until done"
    end
    iterations -= 1
end
puts "Done"

我想知道是否有一种更"Ruby的方式"来优化/编写这些代码。有人有什么想法吗？

Answer 1

10.downto(1) do |iteration|
  puts "#{iteration} iteration#{'s' if iteration > 1} until done"
end
puts 'Done'

Answer 2

require 'active_support/inflector'
10.downto(1).each { |i| puts "#{i} #{'iteration'.pluralize(i)} until done" }
puts 'Done'

Answer 3

计数向上使用范围对象

如果不需要倒计数，可以通过迭代Range对象来进一步简化。例如：

(1..10).each { |i| puts "#{i} iterations completed" }

这将打印：

1 iterations completed
2 iterations completed
3 iterations completed
4 iterations completed
5 iterations completed
6 iterations completed
7 iterations completed
8 iterations completed
9 iterations completed
10 iterations completed

反转范围

如果您已经有一个Range对象，并且希望在不必调用Integer#downto的情况下倒计时，也可以反转Range。例如：

(1..10).to_a.reverse.each  { |i| puts i }