python对象的存储与读取

#一、在文件中存储并解析Python对象'''"""在data.txt中存储Python对象，write写入的必须是字符串对象"""X,Y,Z = 43,44,45S = 'SPAM'D = {'a':1,'b':2}L = [1,2,3]F = open("data.txt",'w')F.write(S+'\n')F.write(("%s,%s,%s\n") % (X,Y,Z))F.write(str(D) + '$' + str(L) + '\n')F.close()"""读取python对象并逐一解析出来"""R = open("data.txt",'r')line0 = R.readline()line0.rstrip()"""输出结果：string: SPAM"""print "string:",line0,"""1、使用split方法将字符串拆分为字符串列表2、使用列表推导获得需要的数字列表输出结果：numbers: [43, 44, 45]"""line1 = R.readline()numbers = [int(part) for part in line1.split(',')]print "numbers:",numbers"""使用eval表达式解析列表&字典,eval可将字符串当做可执行代码运行结果：objects: [{'a': 1, 'b': 2}, [1, 2, 3]]"""line2 = R.readline()objects = [eval(part) for part in line2.split("$")]print "objects:",objectsR.close()#二、用pickle存储python原生对象"""直接使用内置模块pickle的dump()、load()方法实现字典的写入和读取，不需要解析处理"""import pickleD1 = {'A':1,'B':2}F1 = open("datafile.pkl",'wb')pickle.dump(D1,F1)F1.close()F11 = open("datafile.pkl",'rb')data = pickle.load(F11)print "data:",dataF11.close()#三、文件中打包二进制数据的存储与解析"""1、使用内置模块struct的pack方法将数据打包，然后使用write方法写入2、使用内置模块struct的unpack方法将读出的数据流进行解包"""import structF2 = open("data.bin","wb")data = struct.pack(">i4sh",7,'spama',8)F2.write(data)F2.close()F22 = open("data.bin",'rb')data2 = F22.read()values = struct.unpack(">i4sh",data)print "datas:",values