Unicode, stdout, and stderr

wxjmfauth at gmail.com wxjmfauth at gmail.com
Tue Jul 22 08:54:01 CEST 2014


Le mardi 22 juillet 2014 08:18:08 UTC+2, Frank Millman a écrit :
> Hi all
> 
> 
> 
> This is not important, but I would appreciate it if someone could explain 
> 
> the following, run from cmd.exe on Windows Server 2003 -
> 
> 
> 
> C:\>python
> 
> Python 3.4.1 (v3.4.1:c0e311e010fc, May 18 2014, 10:38:22) [MSC v.1600 32 bit 
> 
> (In
> 
> tel)] on win32
> 
> Type "help", "copyright", "credits" or "license" for more information.
> 
> >>> x = '\u2119'
> 
> >>> x  # this uses stderr
> 
> '\u2119'
> 
> >>> print(x)  # this uses stdout
> 
> Traceback (most recent call last):
> 
>   File "<stdin>", line 1, in <module>
> 
>   File "C:\Python34\lib\encodings\cp437.py", line 19, in encode
> 
>     return codecs.charmap_encode(input,self.errors,encoding_map)[0]
> 
> UnicodeEncodeError: 'charmap' codec can't encode character '\u2119' in 
> 
> position
> 
> 0: character maps to <undefined>
> 
> >>>
> 
> 
> 
> It seems that there is a difference between writing to stdout and writing to 
> 
> stderr. My questions are -
> 
> 
> 
> 1. What is the difference?
> 
> 
> 
> 2. Is there an easy way to get stdout to behave the same as stderr?
> 
> 
> 
%%%%%%%%%%


This is an example of what I explained in my
last msg in the "Python 3 is killing Python".

Quote of my comment:

"Generally, speaking, this is a perpetual annoyment
(to be polite) in Python. Python is always attempting
to find a solution for the "Python user", to enforce a
coding usage instead of letting the user/programmer
doing the task correctly.

I'm not alone to think like this and I have seen
many times people complaining about this."

----

Something different.

>>> x = '\u2119'
>>> x  # this uses stderr

This not stderr, but stdout (I doubt you redirected it).
What you see is the *representation* of x

>>> print(x)  # this uses stdout

Correct. This is supposed to print, understand desplay,
the "x as litteral" (I do not find a proper name).

Solution:
Work properly. Undestand the coding of chars eco-system as a whole
correctly.

In short: *encode*

I explained that many times (including on wx-list).

jmf



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