ruby中的三向比较

什么是确保三个变量在ruby中都相等的最简洁方法？ 例如

dog = 'animal' cat = 'animal' chicken = 'animal' shoe = 'clothing' # Something like this...which doesn't work dog == cat == chicken # true dog == cat == shoe # false 

Answer 1

三个元素最简洁的方法是（抱歉让你失望）：

 dog == cat && cat == chicken 

当然，如果你想……你总能变得聪明……

 [dog, cat, chicken] == [dog] * 3 [dog, cat, chicken].uniq.length == 1 

…但这并没有真正使代码更简洁（或可读）。

如果你想要一个可以比较任意多个元素的可重用函数，我会做这样的事情：

 def all_equal?(*elements) elements.all? { |x| x == elements.first } end 

Answer 2

 dog == cat && dog == chicken 

Answer 3

给出数字进行比较：

dog =’animal’

cat =’animal’

chicken =’animal’

鞋=’衣服’

创建一个数组：

 arr = [dog, cat, chicken, shoe] arr_length = arr.reject { |a| a != dog }.length if arr_length == 0 puts "All numbers are equal" end