Python--026字典：当索引不好用时2

游戏小虾米

Tip：


一，理论


二，应用

>>> dict1 ={}
>>> dict1.fromkeys((1,2,3))              # fromkeys方法
{1: None, 2: None, 3: None}
>>> dict1.fromkeys((1,2,3),"Number")
{1: 'Number', 2: 'Number', 3: 'Number'}
>>> dict1.fromkeys((1,2,3),("one","two","three"))
{1: ('one', 'two', 'three'), 2: ('one', 'two', 'three'), 3: ('one', 'two', 'three')}

1 keys
>>> dict1 = dict1.fromkeys(range(32),'赞')
>>> dict1
{0: '赞', 1: '赞', 2: '赞', 3: '赞', 4: '赞', 5: '赞', 6: '赞', 7: '赞', 8: '赞', 9: '赞', 10: '赞', 11: '赞', 12: '赞', 13: '赞', 14: '赞', 15: '赞', 16: '赞', 17: '赞', 18: '赞', 19: '赞', 20: '赞', 21: '赞', 22: '赞', 23: '赞', 24: '赞', 25: '赞', 26: '赞', 27: '赞', 28: '赞', 29: '赞', 30: '赞', 31: '赞'}
012345678910111213141516171819202122232425262728293031
>>> for eachKey in dict1.keys():
        print(eachKey, end = ' ')

2 values
>>> for eachValue in dict1.values():
        print(eachValue, end = " ")

       
赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞 赞

3 items
>>> for eachItem in dict1.items():
        print(eachItem, end = " ")

       
(0, '赞') (1, '赞') (2, '赞') (3, '赞') (4, '赞') (5, '赞') (6, '赞') (7, '赞') (8, '赞') (9, '赞') (10, '赞') (11, '赞') (12, '赞') (13, '赞') (14, '赞') (15, '赞') (16, '赞') (17, '赞') (18, '赞') (19, '赞') (20, '赞') (21, '赞') (22, '赞') (23, '赞') (24, '赞') (25, '赞') (26, '赞') (27, '赞') (28, '赞') (29, '赞') (30, '赞') (31, '赞')

4 get
>>> dict1.get(32, '木有')              #没有键值，直接打印第二个参数，有键值，直接返回相应的值
'木有'
>>> dict1.get(31, '木有')
'赞'

5 成员操作符 in， not in
>>> 31 in dict1
True
>>> 32 in dict1
False

6 clear()
>>> dict1.clear()          #清除方法， 用dict1 = {} 有隐患，直接使用clear（）
>>> dict1
{}

7 update()  #更新其他字典
8 setdefaults() # 添加字典文件
9 pop() 弹出某一个索引及其vuale
9 popitem()  随机弹出一组key+value


三，课后练习