set和dict

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

# dict 属于Mapping类型

a = {}
print(isinstance(a,MutableMapping))

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
new_list = [‘liming1‘,‘liming2‘]

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

print(new_dict)

# 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)