Using pickle.dump - TypeError: must be str, not bytes
I'm using python3.3 and I'm having a cryptic error when trying to pickle a simple dictionary.
Here is the code:
import os
import pickle
from pickle import *
os.chdir('c:/Python26/progfiles/')
def storvars(vdict):
f = open('varstor.txt','w')
pickle.dump(vdict,f,)
f.close()
return
mydict = {'name':'john','gender':'male','age':'45'}
storvars(mydict)
and I get:
Traceback (most recent call last):
File "C:/Python26/test18.py", line 31, in <module>
storvars(mydict)
File "C:/Python26/test18.py", line 14, in storvars
pickle.dump(vdict,f,)
TypeError: must be str, not bytes
The output file needs to be opened in binary mode:
f = open('varstor.txt','w')
needs to be:
f = open('varstor.txt','wb')
Just had same issue. In Python 3, Binary modes 'wb', 'rb' must be specified whereas in Python 2x, they are not needed. When you follow tutorials that are based on Python 2x, that's why you are here.
import pickle
class MyUser(object):
def __init__(self,name):
self.name = name
user = MyUser('Peter')
print("Before serialization: ")
print(user.name)
print("------------")
serialized = pickle.dumps(user)
filename = 'serialized.native'
with open(filename,'wb') as file_object:
file_object.write(serialized)
with open(filename,'rb') as file_object:
raw_data = file_object.read()
deserialized = pickle.loads(raw_data)
print("Loading from serialized file: ")
user2 = deserialized
print(user2.name)
print("------------")
pickle uses a binary protocol, hence only accepts binary files. As the document said in the first sentence, "The pickle module implements binary protocols for serializing and de-serializing".
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pickle.dump()andpickle.load(). Both places, this was mentioned only in passing near the middle of the function explanation. Someone should make this clearer.