比较ruby数组的数组

Question

我有这个数组

a = [[1,2,3,4,5],[2,3,6],[2,8,9]]

如何获得所有数组的交集a？它应该是相同的a[0]&a[1]&a[2],它是:

[2]

Answer 1

a = [[1 ,2, 3, 4, 5], [2, 3, 6], [2, 8, 9]]

a.inject(:&)
# => [2]