set和dict

Posted 2022-02-04 richiewlq

dict属于mapping类型

from collections.abc import Mapping,MutableMapping
from collections.abc import __all__

# dict 属于Mapping类型

a = 
print(isinstance(a,MutableMapping))

copy 浅拷贝

a = 
    "liming1":"company":"tencent1",
    "liming2":"company":"tencent2",


# clear
""" D.clear() -> None.  Remove all items from D. """
# a.clear()

#copy 浅拷贝
""" D.copy() -> a shallow copy of D """
new_dict = a.copy()
new_dict[‘liming1‘][‘company‘] = ‘tencent3‘

print(a)
print(new_dict)

###########
‘liming1‘: ‘company‘: ‘tencent3‘, ‘liming2‘: ‘company‘: ‘tencent2‘
‘liming1‘: ‘company‘: ‘tencent3‘, ‘liming2‘: ‘company‘: ‘tencent2‘

fromkeys

# fromkeys
new_list = [‘liming1‘,‘liming2‘]

new_dict = dict.fromkeys(new_list,‘company‘:‘tencent‘)

print(new_dict)

update

# update

new_dict.update(‘lisa‘:"company":"tencent2")
new_dict.update(‘liming2‘:"company":"tencent2")
new_dict.update(jenny=‘company‘:‘beijing‘)
new_dict.update([(‘jenny‘,‘company‘:‘shanghai‘)])
print(new_dict)