字典

表示形式

dic_1={'a':22,'b':'f'}
print(dic_1)
print('*'*50)
dic_2=dict(a=1,b=2,c=5)
print(dic_2)

{'a': 22, 'b': 'f'}
**************************************************

存取

dic={'a':1,"b":2}
print(f"first dic['a']:{dic['a']}")
dic['a']=4
print(f"second dic['a']:{dic['a']}")

first dic['a']:1
second dic['a']:4

len长度

print(len(dic))

2

not in or in

print(2 in dic)
print('a' in dic)

False
True

del删除

del dic['b']
print(dic)
print(dic.get('a'))
print(dic.get('b'))
print(dic)

{'a': 4}
4
None

pop删除

dic.pop('a')
print(dic)

{}

循环

dic={'a':1,"b":2}
for k,v in dic.items():
    print(k,v)

a 1
b 2

get取值

print(dic.get('a'))

1

print(dic.get('a'))
dic1 = {'a': 1, 'b': 2}
dic2 = {'c': 3}
dic1.update(dic2)
print(f"dic1: {dic1}")

1
dic1: {'a': 1, 'b': 2, 'c': 3}

fromkeys

dic = dict.fromkeys(['name', 'age', 'sex'], None)
print(f"dic: {dic}")

dic: {'name': None, 'age': None, 'sex': None}

---------------------------------------------------------------------------

TypeError Traceback (most recent call last)

Cell In[11], line 1
----> 1 dic = dict.fromkeys(['name', 'age', 'sex'], 1,2,3)
2 print(f"dic: {dic}")

TypeError: fromkeys expected at most 2 arguments, got 4