如何测试数组中的所有项是否相同?

I can generate a few lines of code that will do this but I'm wondering if there's a nice clean Rubyesque way of doing this. In case I haven't been clear, what I'm looking for is an array method that will return true if given (say) [3,3,3,3,3] or ["rabbits","rabbits","rabbits"] but will return false with [1,2,3,4,5] or ["rabbits","rabbits","hares"].

我可以生成几行代码来做这个但我想知道是否有一个干净的Rubyesque方法。如果我还不清楚，我要找的是一个数组方法，如果给定(比方说)[3,3,3,3,3]或["兔子"，"兔子"，"兔子"]，但将返回false，但将返回false，[1,2,3,4,5]或["兔子"，"兔子"，"兔子"]。

Thanks

谢谢

5 个解决方案

#1

class Array
  def same_values?
    self.uniq.length == 1
  end
end


[1, 1, 1, 1].same_values?
[1, 2, 3, 4].same_values?

What about this one? It returns false for an empty array though, you can change it to <= 1 and it will return true in that case. Depending on what you need.

这一个怎么样?对于空数组，它返回false，您可以将它更改为<= 1，在这种情况下，它将返回true。这取决于你需要什么。

#2

You can use Enumerable#all? which returns true if the given block returns true for all the elements in the collection.

您可以使用可列举的# ?如果给定的块对集合中的所有元素返回true，则返回true。

array.all? {|x| x == array[0]}

(If the array is empty, the block is never called, so doing array[0] is safe.)

(如果数组为空，则不会调用该块，因此使用数组[0]是安全的。)

#3

I too like preferred answer best, short and sweet. If all elements were from the same Enumerable class, such as Numeric or String, one could use

我也喜欢最好的、简短的和甜蜜的回答。如果所有元素都来自相同的可枚举类，例如数字或字符串，则可以使用

def all_equal?(array) array.max == array.min end

#4

I used to use :

我曾经用过:

def add_equal?(arr) arr.reduce { |x,y| x == y ? x : nil } end

It may fail when arr contains nil.

当arr包含nil时，它可能会失败。

#5

I would use:

我将使用:

array = ["rabbits","rabbits","hares", nil, nil]
array.uniq.compact.length == 1

#1

class Array
  def same_values?
    self.uniq.length == 1
  end
end


[1, 1, 1, 1].same_values?
[1, 2, 3, 4].same_values?