Ruby-on-rails rails - 查找多个数组之间的交集
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rails - Finding intersections between multiple arrays
提问by Alex
I am trying to find the intersection values between multiple arrays.
我试图找到多个数组之间的交集值。
for example
例如
code1 = [1,2,3]
code2 = [2,3,4]
code3 = [0,2,6]
So the result would be 2
所以结果是 2
I know in PHP you can do this with array_intersect
我知道在 PHP 中你可以用 array_intersect 做到这一点
I wanted to be able to easily add additional array so I don't really want to use multiple loops
我希望能够轻松添加额外的数组，所以我真的不想使用多个循环
Any ideas ?
有任何想法吗 ？
Thanks, Alex
谢谢，亚历克斯
回答by Anurag
回答by Fotios
If you want a simpler way to do this with an array of arrays of unknown length, you can use inject.
如果你想用一种更简单的方法来处理未知长度的数组，你可以使用注入。
> arrays = [code1,code2,code3]
> arrays.inject(:&) # Ruby 1.9 shorthand
=> [2]
> arrays.inject{|codes,x| codes & x } # Full syntax works with 1.8 and 1.9
=> [2]
回答by Marian13
Ruby 2.7 introduced Array#intersectionmethod to match the more succinct Array#&.
Ruby 2.7 引入了Array#intersection方法来匹配更简洁的Array#&。
So, now, [1, 2, 3] & [2, 3, 4] & [0, 2, 6]can be rewritten in a more verbose way, e.g.
所以，现在，[1, 2, 3] & [2, 3, 4] & [0, 2, 6]可以用更详细的方式重写，例如
[1, 2, 3].intersection([2, 3, 4]).intersection([0, 2, 6])
# => [2]
[1, 2, 3].intersection([2, 3, 4], [0, 2, 6])
# => [2]
