[Python-ideas] Replacing the standard IO streams (was Re: changing sys.stdout encoding)

[Paul Moore]

On 10 June 2012 21:28, MRAB <python at mrabarnett.plus.com> wrote:
> On 10/06/2012 21:07, Paul Moore wrote:
>>
>> On 10 June 2012 20:01, MRAB<python at mrabarnett.plus.com>  wrote:
>>>
>>>  On 10/06/2012 19:34, Paul Moore wrote:
>>>>
>>>>
>>>>  On 10 June 2012 19:12, MRAB<python at mrabarnett.plus.com>    wrote:
>>>>>
>>>>>
>>>>>   On 10/06/2012 17:41, Stephen J. Turnbull wrote:
>>>>>>
>>>>>>
>>>>>>   I am a little concerned with MRAB's report that
>>>>>>
>>>>>>       import sys
>>>>>>       print("hello")
>>>>>>       sys.stdout.flush()
>>>>>>       sys.stdout = open(sys.stdout.fileno(), 'w', encoding='utf-8')
>>>>>>       print("hello")
>>>>>>
>>>>>>   doesn't work as expected, though.  (It does work for me on Mac OS X,
>>>>>>   both as above -- of course there are no '\r's in the output -- and
>>>>>>   with 'print("hello", end="\r\n")'.)
>>>>>>
>>>>>   That's actually Python 3.1. From Python 3.2 it's slightly different,
>>>>>   but still not quite right:
>>>>>
>>>>>   Python 3.1:     "hello\r\nhello\r\r\n"
>>>>>   Python 3.2:     "hello\nhello\r\n"
>>>>>   Python 3.3.0a4: "hello\nhello\r\n"
>>>>>
>>>>>   All on Windows.
>>>>
>>>>
>>>>
>>>>  Not here (Win 7 32-bit):
>>>>
>>>>  PS D:\Data>    type t.py
>>>>  import sys
>>>>  print("Hello!")
>>>>  sys.stdout.flush()
>>>>
>>>>  sys.stdout = open(sys.stdout.fileno(), 'w', encoding='utf-8')
>>>>  print("Hello!")
>>>>  PS D:\Data>    py -3.2 t.py | od -c
>>>>  0000000   H   e   l   l   o   !  \r  \n   H   e   l   l   o   !  \r  \n
>>>>  0000020
>>>>
>>>  I'm using Windows XP Pro (32-bit), initially sys.stdout.encoding ==
>>>  "cp1252".
>>
>>
>> PS D:\Data>  py -3 -c "import sys; print(sys.stdout.encoding)"
>> cp850
>>
>> This is at the console (Powershell) - are you running from within
>> something like idle, or a GUI environment?
>>
> It's at the system command prompt. When I redirect the script's stdout to a
> file
> (on the command line using ">output.txt") I get those 15 bytes from Python
> 3.2.
>
> Your output appears to be 32 bytes (the second line starts with
> "0000020").

Well spotted - PowerShell does funny things with Unicode in pipes, I'd
forgotten. Indeed, I get the same output as you from cmd.

Odd.
Paul