python shelve 使用实例

import shelve

d = shelve.open("tom")
d["name"] = "Tom"
print(d["name"])  # Tom
d.close()

import shelve

d = shelve.open("tom")
d["name"] = "Tom"
d.close()

print(d["name"])  # ValueError: invalid operation on closed shelf

import shelve

d = shelve.open("namelist", writeback=True)

d["name"] = "Tom"
d["age"] = 18
d.close()


d = shelve.open("namelist")

for k in d:  # 遍历所有的key
    print(k)  # name age

for k in d.keys():  # 遍历所有key
    print(k)  # name age

for k, v in d.items():  # 遍历所有的键-值对
    print(k, v)  # name Tom   age 18
d.close()

import shelve

d = shelve.open("namedict")
d["one"] = {"name": "Tom", "age": 18, "hobby": "football"}
d.close()

import shelve

d = shelve.open("namedict")
d["one"]["name"] = "Linda"
d.close()


d = shelve.open("namedict")
print(d["one"])  # {'name': 'Tom', 'age': 18, 'hobby': 'football'}
d.close()

import shelve

d = shelve.open("namedict", writeback=True)
d["one"]["name"] = "Linda"
d.close()


d = shelve.open("namedict")
print(d["one"])  # {'name': 'Linda', 'age': 18, 'hobby': 'football'}
d.close()

import shelve

d = shelve.open("namedict", writeback=True)
del d["one"]
d.close()


d = shelve.open("namedict")
print(d["one"])  # KeyError: b'one' 报错
d.close()