打开文件时出错。 蟒蛇

Question

I trying to open file and met some problem:

TypeError: coercing to Unicode: need string or buffer, NoneType found

Here is the code example:

a = open(fname, "rb").read(255)

Whats wrong with the code?

Answer 1

fname is None , not a string:

>>> open(None)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: coercing to Unicode: need string or buffer, NoneType found

You'll have to fix how you set fname or explicitly guard against it being None .