Question

我尝试使用pickle模块使用二进制模式写入文件。这是一个例子：

    import pickle
    file = open("file.txt","wb")
    dict = {"a":"b","c":"d"}
    pickle.dump(dict, file)
    file.close()

但是这种方法删除了之前写的其他词。如何在不删除文件中的其他内容的情况下编写？

Answer 1

You can concatenate pickled objects in a file, so it's not necessary to read the file in and rewrite it. You simply need to append to the file, rather than overwriting it.

Replace:

file = open("file.txt","wb")

With:

file = open("file.txt","ab")

For more information on the file modes available and what they do, see the documentation.

And remember that you'll need multiple pickle.load()s to unpickle the data.

Answer 2

您需要附加到原始文件，但首先取消内容（我假设原始文件有腌制内容）。你正在做的只是用一个新的pickle对象覆盖现有文件

import pickle

#create the initial file for test purposes only
obj = {"a":"b","c":"d"}
with open("file.txt","wb") as f:
    pickle.dump(obj, f)

#reopen and unpickle the pickled content and read to obj
with open("file.txt","rb") as f:
    obj = pickle.load(f)
    print(obj)

#add to the dictionary object 
obj["newa"]="newb"
obj["newc"]="newd"

with open("file.txt","wb") as f:
    pickle.dump(obj, f)

#reopen and unpickle the pickled content and read to obj
with open("file.txt","rb") as f:
    obj = pickle.load(f)
    print(obj)

附加到pickle文件而不删除

2 个答案: