Python学习日记－2
＊使用pickle处理数据存储，类似于java中的serialization，是将对象转化为二进制码存入文件中，主要函数pickle.dump(obj,file),pickle.load(file)＊在每个文件加入后缀.pkl，实现逐行数据存入
＊使用shelve，实现dictionary数据的隐形固态存储，具体实现方式与pickle相同
[*]import pickle
[*]dbfile=open('people-pickle','wb') #二进制写
[*]pickle.dump(db, dbfile)
[*]dbfile.close()
[*]
[*]dbfile=open('people-pickle','rb') ＃二进制读
[*]db=pickle.load(dbfile)
[*]print db
[*]
[*]import pickle
[*]for (key, record) in [('bob', bob), ('tom', tom), ('sue', sue)]:
[*] recfile = open(key + '.pkl', 'wb')
[*] pickle.dump(record, recfile)
[*] recfile.close()
[*]
[*]import pickle, glob
[*]for filename in glob.glob('*.pkl'):＃当前文件夹中所有以.pkl为后缀的文件
[*] recfile = open(filename, 'rb')
[*] record = pickle.load(recfile)
[*] print(filename, '=>\n ', record)
[*]suefile = open('sue.pkl', 'rb')
[*]print(pickle.load(suefile)['name'])
[*]
[*]import shelve
[*]db = shelve.open('people-shelve')
[*]db['bob'] = bob
[*]db['sue'] = sue
[*]db.close()
[*]
[*]db = shelve.open('people-shelve')
[*]sue=db['sue']
[*]sue['name']='Susie Q' #不能直接赋值给db['sue']['name']
[*]db['sue']=sue
[*]db.close
[*]
[*]db = shelve.open('people-shelve')
[*]print db
[*]db.close()
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