如何显示方法参数中的nil？

问题描述

这是我在这里的第一篇文章，我是一个超级初学者，我想解决一个问题。

好吧，我想知道如何在方法的参数中显示nil。 这是我尝试的代码，但是预期结果不符合我的期望，您能帮我吗？谢谢。

def who_is_bigger(a,b,c)
  max_number = 84
  the_nil = c
  if max_number == a
    puts "a is bigger"
  elsif max_number == b
    puts "b is bigger"
  elsif max_number == c
    puts "c is bigger"
  elsif the_nil == nil
    puts "nil detected"
  else
    puts "nil detected"
  end
end
  
puts who_is_bigger(84,42,nil)
puts who_is_bigger(nil,21)
puts who_is_bigger(84,21)
puts who_is_bigger(42,84,21,84)

我的终端将其退回；

a is bigger
nil detected
a is bigger
b is bigger
c is bigger

但是我想要这个；

nil detected
nil detected
a is bigger
b is bigger
c is bigger

解决方法

您需要在其他条件之前先进行nil检查。

def who_is_bigger(a,b,c)
  if [a,c].include?(nil)
    puts "nil detected"
    return
  end
  max_number = 84
  if max_number == a
    puts "a is bigger"
  elsif max_number == b
    puts "b is bigger"
  elsif max_number == c
    puts "c is bigger"
  else
    puts "nil detected" # this should really be max_number not found
  end
end