Tomas Sedovic Tomas Sedovic - 6 months ago 11
Python Question

Convert bytes to a Python string

I'm using this code to get standard output from an external program:

>>> from subprocess import *
>>> command_stdout = Popen(['ls', '-l'], stdout=PIPE).communicate()[0]


The communicate() method returns an array of bytes:

>>> command_stdout
b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar 3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar 3 07:03 file2\n'


However, I'd like to work with the output as a normal Python string. So that I could print it like this:

>>> print(command_stdout)
-rw-rw-r-- 1 thomas thomas 0 Mar 3 07:03 file1
-rw-rw-r-- 1 thomas thomas 0 Mar 3 07:03 file2


I thought that's what the binascii.b2a_qp() method is for, but when I tried it, I got the same byte array again:

>>> binascii.b2a_qp(command_stdout)
b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar 3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar 3 07:03 file2\n'


Does anybody know how to convert the bytes value back to string? I mean, using the "batteries" instead of doing it manually. And I'd like it to be ok with Python 3.

Answer

You need to decode the bytes object to produce a string:

>>> b"abcde"
b'abcde'

# utf-8 is used here because it is a very common encoding, but you
# need to use the encoding your data is actually in.
>>> b"abcde".decode("utf-8") 
'abcde'
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