Python序列化

2019-11-11 02:36:16

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一旦数据被序列化，就可以把它写入到文件、socket、管道等中。之后你可以读取这个文件，读取这些数据结构具有相同值的新对象。

# -*- coding: utf-8 -*-try: import cPickle as pickleexcept: import pickleimport pPRintdata1 = [{'a': 'A', 'b': 2, 'c': 3.0}]print 'BEFORE:',pprint.pprint(data1)data1_string = pickle.dumps(data1)data2 = pickle.loads(data1_string)print 'AFTER:',pprint.pprint(data2)print 'SAME?:', (data1 is data2)print 'EQUAL?:', (data1 == data2)

输出：

BEFORE:[{'a': 'A', 'b': 2, 'c': 3.0}]AFTER:[{'a': 'A', 'b': 2, 'c': 3.0}]SAME?: FalseEQUAL?: True

在处理自定义类时，应该保证这些被序列化的类会在进程名空间出现。只要数据实例才能被序列化，而不能是定义的类。在反序列化时，类的名字被用于寻找构造器以便创建新对象。dump_obj.py将一个类实例写入到文件中，load_obj.py将刚才序列化的对象装载进来。

dump_obj.py

# -*- coding: utf-8 -*-try: import cPickle as pickleexcept: import pickleclass SimpleObject(object): def __init__(self, name): self.name = name l = list(name) l.reverse() self.name_backwards = ''.join(l)if __name__ == '__main__': data = [] data.append(SimpleObject('pickle')) data.append(SimpleObject('cPickle')) data.append(SimpleObject('last')) out_s = open('testPickle', 'wb') try: for o in data: print 'WRITING: %s (%s)' % (o.name, o.name_backwards) pickle.dump(o, out_s) finally: out_s.close()

输出：

WRITING: pickle (elkcip)WRITING: cPickle (elkciPc)WRITING: last (tsal)

load_obj.py

# -*- coding: utf-8 -*-try: import cPickle as pickleexcept: import picklefrom dump_obj import SimpleObjectin_s = open('testPickle', 'rb')try: while True: try: o = pickle.load(in_s) except EOFError: break else: print 'READ: %s (%s)' % (o.name, o.name_backwards)finally: in_s.close()

输出：

READ: pickle (elkcip)READ: cPickle (elkciPc)READ: last (tsal)

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