python - 我可以在内存中 pickle Python 对象而不是物理文件吗？

Question

这个问题在这里已经有了答案:





Pickle.dump to variable

(3 个回答)


3年前关闭。




我已经看到并编写了用 Python pickle 对象的代码。但它们都创建物理文件来包含数据。我希望我将数据写入内存并读取并 pickle 并传输它。

甚至有可能吗？

from PIL import ImageGrab
import io
import codecs
import pickle


# Model class to send Process Data to the server
class ProcessData:
 process_id = 0
 project_id = 0
 task_id = 0
 start_time = 0
 end_time = 0
 user_id = 0
 weekend_id = 0

# Model class to send image data to the server
class ProcessScreen:
 process_id = 0
 image_data = bytearray()


image_name = "Dharmindar_screen.jpg"
ImageGrab.grab().save(image_name,"JPEG")

image_data = None
with codecs.open(image_name,'rb') as image_file:
 image_data = image_file.read()



serialized_process_data = io.BytesIO()

process_data = ProcessData()
process_data.process_id = 1
process_data.project_id = 2
process_data.task_id = 3
process_data.user_id = 4
process_data.weekend_id = 5
process_data.start_time = 676876
process_data.end_time = 787987

process_screen = ProcessScreen()
process_screen.process_id = process_data.process_id
process_screen.image_data = image_data


prepared_process_data = (process_data, process_screen)

process_data_serializer = pickle.Pickler()
process_data_serializer(serialized_process_data).dump(prepared_process_data)

print('Data serialized.')


if process_data_serializer is not None:
    d = process_data_serializer.getvalue()
    deserialized_data = None
    with open(d, 'rb') as serialized_data_file:
        process_deserializer = pickle.Unpickler(serialized_data_file)
        deserialized_data = process_deserializer.load()
else:
    print('Empty')

上面的代码抛出 TypeError: Required argument 'file' (pos 1) not found

Answer 1

您传递给 pickle.dump 的 File 对象只需要一个写方法，见https://docs.python.org/2/library/pickle.html#pickle.dump

file must have a write() method that accepts a single string argument. It can thus be a file object opened for writing, a StringIO object, or any other custom object that meets this interface.

例如，您甚至可以创建自己的类来存储 pickle 数据，而不是使用 StringIO 对象

class MyFile(object):
    def __init__(self):
        self.data = []
    def write(self, stuff):
        self.data.append(stuff)

然后只是pickle到这个类的一个实例:

class ExampleClass(object):
    def __init__(self, x):
        self.data = x  
a = ExampleClass(123)
f = MyFile()
pickle.dump(a, f)

正如@rawing 所提议的，另一种选择是使用 pickle.dumps这将直接返回一个您可以使用的字符串，比较 here .