Unicode blues in Python3
Gary Herron
gherron at islandtraining.com
Tue Mar 23 14:11:15 EDT 2010
nn wrote:
> I know that unicode is the way to go in Python 3.1, but it is getting
> in my way right now in my Unix scripts. How do I write a chr(253) to a
> file?
>
Python3 make a distinction between bytes and string(i.e., unicode)
types, and you are still thinking in the Python2 mode that does *NOT*
make such a distinction. What you appear to want is to write a
particular byte to a file -- so use the bytes type and a file open in
binary mode:
>>> b=bytes([253])
>>> f = open("abc", 'wb')
>>> f.write(b)
1
>>> f.close()
On unix (at least), the "od" program can verify the contents is correct:
> od abc -d
0000000 253
0000001
Hope that helps.
Gary Herron
> #nntst2.py
> import sys,codecs
> mychar=chr(253)
> print(sys.stdout.encoding)
> print(mychar)
>
> > ./nntst2.py
> ISO8859-1
> ý
>
> > ./nntst2.py >nnout2
> Traceback (most recent call last):
> File "./nntst2.py", line 5, in <module>
> print(mychar)
> UnicodeEncodeError: 'ascii' codec can't encode character '\xfd' in
> position 0: ordinal not in range(128)
>
>
>> cat nnout2
>>
> ascii
>
> ..Oh great!
>
> ok lets try this:
> #nntst3.py
> import sys,codecs
> mychar=chr(253)
> print(sys.stdout.encoding)
> print(mychar.encode('latin1'))
>
>
>> ./nntst3.py
>>
> ISO8859-1
> b'\xfd'
>
>
>> ./nntst3.py >nnout3
>>
>
>
>> cat nnout3
>>
> ascii
> b'\xfd'
>
> ..Eh... not what I want really.
>
> #nntst4.py
> import sys,codecs
> mychar=chr(253)
> print(sys.stdout.encoding)
> sys.stdout=codecs.getwriter("latin1")(sys.stdout)
> print(mychar)
>
> > ./nntst4.py
> ISO8859-1
> Traceback (most recent call last):
> File "./nntst4.py", line 6, in <module>
> print(mychar)
> File "Python-3.1.2/Lib/codecs.py", line 356, in write
> self.stream.write(data)
> TypeError: must be str, not bytes
>
> ..OK, this is not working either.
>
> Is there any way to write a value 253 to standard output?
>
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