python 中List 与dictionary

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1 List 中的平行赋值，注意其中的last_name前面有一个*，表示如果 List中元素个数大于待赋值的对象个数的话，表示这个对象是一个子list

    def test_parallel_assignments_with_extra_values(self):
        title, first_names, *last_name = ["Sir", "Ricky", "Bobby", "Worthington"]
        self.assertEqual("Sir", title)
        self.assertEqual("Ricky", first_names)
        self.assertEqual(["Bobby","Worthington"], last_name)

2 这里平行赋值，交换变量，这个牛，不需要第三个变量

    def test_swapping_with_parallel_assignment(self):
        first_name = "Roy"
        last_name = "Rob"
        first_name, last_name = last_name, first_name
        self.assertEqual("Rob", first_name)
        self.assertEqual("Roy", last_name)

3 dictionary表示方法是{}，生成dictionary项数据

def test_making_a_dictionary_from_a_sequence_of_keys(self):
cards = {}.fromkeys(('red warrior', 'green elf', 'blue valkyrie', 'yellow dwarf', 'confused looking zebra'), 42)

        self.assertEqual(5, len(cards))
        self.assertEqual(42, cards['green elf'])
        self.assertEqual(42, cards['yellow dwarf'])