python pickle模块 数据 追加、读取、持久化

导入

import pickle

转换

data = [{'title': 't1', 'url': 'one'}, {'title': 't2', 'url': 'two'}]

data_dumps = pickle.dumps(data)
print(type(data_dumps))  # <class 'bytes'>

data_loads = pickle.loads(data_dumps)
print(type(data_loads))  # <class 'list'>

转换 + 文件操作

data = [{'title': 't1', 'url': 'one'}, {'title': 't2', 'url': 'two'}]

# 序列化对象，将结果数据流写入到文件对象中
f_dump = open('any_file_name', 'wb')
pickle.dump(data, f_dump)
f_dump.close()

# 反序列化对象，将文件中的数据解析为一个Python对象
f_load = open('any_file_name', 'rb')
data_loads = pickle.load(f_load)
f_load.close()
print(type(data_loads))  # <class 'list'>

追加、读取

pickle 每次序列化生成的字符串有独立头尾，pickle.load() 只会按顺序读取一个完整的结果

# 创建 写入内容
with open('any_file_name', 'wb') as f:
    pickle.dump('pickle_data1', f)
    pickle.dump('pickle_data2', f)

# 追加内容
with open('any_file_name', 'ab') as f:
    pickle.dump('pickle_data3', f)
    pickle.dump('pickle_data4', f)

# 读取所有 pickle 内容
with open('any_file_name', 'rb') as f:
    while 1:
        try:
            one_pickle_data = pickle.load(f)
            print(one_pickle_data)
        except EOFError:
            break