在coffeescript数组中查找重复值的最简单方法

Question

我是coffeescript的新手.请帮我.

如何在数组中找到重复值？

var arr = ['manager','manager','employee','manager',
           'director','employee','manager','operatives'];

在这种情况下,它应该返回['manager','employee'].

Answer 1

试试这个:

    findDuplicates = (array) ->
        keys = {}
        for value in array
            keys[value] ?= 0
            keys[value]++
        (key for key, count of keys when count > 1)

    arr = ['manager','manager','employee','manager', 'director','employee','manager','operatives']
    console.log findDuplicates(arr)