就是每一次迭代k的值，k[0]都作为一个新的元素加入这个列表
>>> alist = [(1, 2), (3, 4), (5, 6)]>>> b = ['a', 'b', 'c']>>> [k[0] for k in alist][1, 3, 5]>>> dict(zip([k[0] for k in alist], b)){1: 'a', 3: 'b', 5: 'c'}
