代码适用于Python 2但不适用于Python3 TypeError：需要类似字节的对象，而不是'str'

Question

The following code works in Python 2.7:

import os
import pickle

modelpath = "models/"

gmm_files = [os.path.join(modelpath,fname) for fname in 
          os.listdir(modelpath) if fname.endswith('.gmm')]

models    = [pickle.load(open(fname,'r')) for fname in gmm_files]

However, when I run the code in Python3, I get the following error from the last line:

TypeError: a bytes-like object is required, not 'str'

In order to get a better idea, I tried printing print([type(open(fname,'r')) for fname in gmm_files]) in both versions and found out that in python 2 the type is <type 'file'> and in Python 3 the type is <class '_io.TextIOWrapper'> .

I've checked out these stackoverflow questions but neither of them have helpful answers for this:

python 3.5: TypeError: a bytes-like object is required, not 'str' when writing to a file

Python sockets error TypeError: a bytes-like object is required, not 'str' with send function

UPDATE

A bunch of the answers here said to change open(fname, 'r') to open(fname, 'rb') but that just leads to another error: UnicodeDecodeError: 'ascii' codec can't decode byte 0xc0 in position 0: ordinal not in range(128)

Answer 1

Ref https://docs.python.org/3.6/library/pickle.html#pickle.load , the file-like object you pass to pickle.load needs to return binary data. Files are opened in text-mode by default, which is why you're seeing this error. If you open the file in binary mode (by adding 'b' to the mode), everything should be work.

Eg

models = [pickle.load(open(fname, 'rb')) for fname in gmm_files]

Answer 2

As the documentation for the pickle.load method says (emphasis mine):

The argument file must have two methods, a read() method that takes an integer argument, and a readline() method that requires no arguments. Both methods should return bytes.

open(stuff, 'r') will open the file for reading text , not raw bytes. Thus, open(stuff, 'r').read will return str , not bytes . To fix that, open the file in binary mode: open(stuff, 'rb') .