python: TypeError: can't write str to text stream

Question

I must be doing something obviously wrong here. But what is it, and how do I fix?

Python 2.6.5 (r265:79096, Mar 19 2010, 21:48:26) [MSC v.1500 32 bit (Intel)         


        

Answer 1

Try:

>>> f1.write(u'bingo')      # u specifies unicode

Reference

Answer 2

Have you tried writing a Unicode string, instead of just a str? I.e.,

fq.write(u"bingo")

I'm on Mac OS X, but when I tried to write a str, I got the error

TypeError: must be unicode, not str

Writing a Unicode string worked, though.

Answer 3

The io module differs from the old open in that it will make a big difference between binary and text files. If you open a file in text mode, reading will return Unicode text objects (called unicode in Python 2 and str in Python 3) and writing requires that you give it unicode objects as well.

If you open in binary mode, you will get 8-bit sequential data back, and that's what you need to write. In Python 2 you use str for this, in Python 3 bytes.

You are using Python 2, and trying to write str to a file opened in text mode. That won't work. Use Unicode.

Answer 4

f = open("test.txt", "w")
f.write('bingo')
f.close()

equivalently,

with open("test.txt", "w") as f:
    f.write('bingo')

and the termination of the block closes the file for you.

Answer 5

The io module is a fairly new python module (introduced in Python 2.6) that makes working with unicode files easier. Its documentation is at: http://docs.python.org/library/io.html

If you just want to be writing bytes (Python 2's "str" type) as opposed to text (Python 2's "unicode" type), then I would recommend you either skip the io module, and just use the builtin "open" function, which gives a file object that deals with bytes:

>>> f1 = open('test.txt','w')

Or, use 'b' in the mode string to open the file in binary mode:

>>> f1 = io.open('test.txt','wb')

Read the docs for the io module for more details: http://docs.python.org/library/io.html