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From: nn on 23 Mar 2010 13:33
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?

#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?
From: nn on 23 Mar 2010 14:09


Rami Chowdhury wrote:
> On Tuesday 23 March 2010 10:33:33 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?
> >
> > #nntst2.py
> > import sys,codecs
> > mychar=chr(253)
> > print(sys.stdout.encoding)
> > print(mychar)
>
> The following code works for me:
>
> $ cat nnout5.py
> #!/usr/bin/python3.1
>
> import sys
> mychar = chr(253)
> sys.stdout.write(mychar)
> $ echo $(cat nnout)
> ý
>
> Can I ask why you're using print() in the first place, rather than writing
> directly to a file? Python 3.x, AFAIK, distinguishes between text and binary > files and will let you specify the encoding you want for strings you write.
>
> Hope that helps,
> Rami
> >
> > > ./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?
>

#nntst5.py
import sys
mychar=chr(253)
sys.stdout.write(mychar)

> ./nntst5.py >nnout5
Traceback (most recent call last):
File "./nntst5.py", line 4, in <module>
sys.stdout.write(mychar)
UnicodeEncodeError: 'ascii' codec can't encode character '\xfd' in
position 0: ordinal not in range(128)

equivalent to print.

I use print so I can do tests and debug runs to the screen or pipe it
to some other tool and then configure the production bash script to
write the final output to a file of my choosing.
From: Gary Herron on 23 Mar 2010 14:11
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?
>


From: nn on 23 Mar 2010 14:46


Gary Herron wrote:
> 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?
> >

Actually what I want is to write a particular byte to standard output,
and I want this to work regardless of where that output gets sent to.
I am aware that I could do
open('nnout','w',encoding='latin1').write(mychar) but I am porting a
python2 program and don't want to rewrite everything that uses that
script.
From: Stefan Behnel on 23 Mar 2010 15:57
nn, 23.03.2010 19:46:
> Actually what I want is to write a particular byte to standard output,
> and I want this to work regardless of where that output gets sent to.
> I am aware that I could do
> open('nnout','w',encoding='latin1').write(mychar) but I am porting a
> python2 program and don't want to rewrite everything that uses that
> script.

Are you writing text or binary data to stdout?

Stefan

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