当我遵循 Ruby rubocop 风格指南并使用 .zero 时方法失败？而不是== 0

Question

我正在尝试完成 Ruby 中的编码练习，如下所示：

TODO: starting with an array of integers, return an array with integers and 'Fizz', 'Buzz' or 'FizzBuzz'

Write a method fizz_buzz, which takes a number as an argument, and return an array of number elements from 1 to number, but replaces some of them according to these rules:

If the number is divisible by 3, then replace it by 'Fizz'

If the number is divisible by 5, then replace it by 'Buzz'

If the number is divisible by both 3 and 5, then replace it by 'FizzBuzz'Write

如果我按照 rubocop style guide，我们被要求在完成任务后使用它，并且按照指示使用 .zero 而不是 == 0?，我的方法失败了，我不明白为什么。

我的风格指南要求的编辑现在失败的解决方案：

def fizz_buzz(number)
  fail ArgumentError, "#{number} is less than 1" if number < 1
  a = [number]
  while number > 1
    number = number - 1
    a.unshift(number)
    a.map! { |x| (x % 15).zero? ? 'FizzBuzz' : x }
    a.map! { |x| (x % 3).zero? ? 'Fizz' : x }
    a.map! { |x| (x % 5).zero? ? 'Buzz' : x }
  end
  a
end

  should return the array [ 1, 2, 'Fizz' ] for number 3 (FAILED - 1)
  should return the array [ 1, 2, 'Fizz', 4, 'Buzz', 'Fizz', 7 ] for number 7 (FAILED - 2)
  should return an array with 'FizzBuzz' at the 15th element of the array (15 is divisible by both 3 and 5) (FAILED - 3)

失败：

  1) fizz_buzz should return the array [ 1, 2, 'Fizz' ] for number 3
     Failure/Error: a.map! { |x| (x % 5).zero? ? 'Buzz' : x }

 NoMethodError:
   undefined method `zero?' for "Fizz":String
 # ./lib/fizz_buzz.rb:12:in `block in fizz_buzz'
 # ./lib/fizz_buzz.rb:12:in `map!'
 # ./lib/fizz_buzz.rb:12:in `fizz_buzz'
 # ./spec/fizz_buzz_spec.rb:13:in `block (2 levels) in <top (required)>'

  2) fizz_buzz should return the array [ 1, 2, 'Fizz', 4, 'Buzz', 'Fizz', 7 ] for number 7
     Failure/Error: a.map! { |x| (x % 5).zero? ? 'Buzz' : x }

 NoMethodError:
   undefined method `zero?' for "Fizz":String
 # ./lib/fizz_buzz.rb:12:in `block in fizz_buzz'
 # ./lib/fizz_buzz.rb:12:in `map!'
 # ./lib/fizz_buzz.rb:12:in `fizz_buzz'
 # ./spec/fizz_buzz_spec.rb:17:in `block (2 levels) in <top (required)>'

  3) fizz_buzz should return an array with 'FizzBuzz' at the 15th element of the array (15 is divisible by both 3 and 5)
     Failure/Error: a.map! { |x| (x % 5).zero? ? 'Buzz' : x }

 NoMethodError:
   undefined method `zero?' for "Fizz":String
 # ./lib/fizz_buzz.rb:12:in `block in fizz_buzz'
 # ./lib/fizz_buzz.rb:12:in `map!'
 # ./lib/fizz_buzz.rb:12:in `fizz_buzz'
 # ./spec/fizz_buzz_spec.rb:21:in `block (2 levels) in <top (required)>'

我的工作解决方案未通过样式指南：

def fizz_buzz(number)
  fail ArgumentError, "#{number} is less than 1" if number < 1
  a = [number]
  while number > 1
    number = number - 1
    a.unshift(number)
    a.map! { |x| (x % 15) == 0 ? 'FizzBuzz' : x }
    a.map! { |x| (x % 3) == 0 ? 'Fizz' : x }
    a.map! { |x| (x % 5) == 0 ? 'Buzz' : x }
  end
  a
end

分配的任务提供的解决方案：

# def fizz_buzz(number)
#   fail ArgumentError, "#{number} should be greater than 1" if number < 1
#   (1..number).map do |i|
#     if (i % 3).zero? && (i % 5).zero?
#       'FizzBuzz'
#     elsif (i % 3).zero?
#       'Fizz'
#     elsif (i % 5).zero?
#       'Buzz'
#     else
#       i
#     end
#   end
# end

Answer 1

既然我们看到了失败的代码，那么失败的原因如下：

您有一个数组 a，我想您打算在其中包含结果。您将数字添加到它前面，并修复需要说 "Fizz" 或 "Buzz" 或 "FizzBuzz" 的数字。这可行，但有一个严重的失败：您在循环的每次迭代中处理数组。如果您只修复一次，就在 return 之前修复它，那就没问题了。但是，这样，会发生什么（例如输入值 4）：

你的数组开始于 4
你运行修复了，但是4很好，不需要修复
你在前面加上3
你运行修复；该数组现在是 ["Fizz", 4]。到目前为止一切顺利。
你在前面加上2；数组是 [2, "Fizz", 4]
您运行修复。 2 无人干预通过，然后轮到 "Fizz"。
"Fizz" 不是数字，因此您不会调用求余运算符 Number#%，而是调用格式化运算符 String#%。字符串 "Fizz" 中没有格式符号，因此格式化运算符没有做任何有趣的事情，并且 returns 字符串 "Fizz".
然后你测试它是否为零。当您尝试 "Fizz" == 0 时，它本来是 "Duh, no" 并且只是 returned false，因为所有类（从 BasicObject 开始）定义 #==。但是 "Fizz".zero? 失败了，因为与 Number#zero? 不同，String#zero? 不是一个东西。

当我遵循 Ruby rubocop 风格指南并使用 .zero 时方法失败？而不是== 0

Method fail when I follow Ruby rubocop style guide and use .zero? instead of == 0

ruby

fizzbuzz