open(False) in python3
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From: geremy condra on 12 May 2010 12:53 On Wed, May 12, 2010 at 1:36 AM, Stefan Behnel <stefan_ml(a)behnel.de> wrote: > Johan Förberg, 12.05.2010 10:05: >> >> On Tue, 11 May 2010 19:27:37 -0300, Gabriel Genellina wrote: >> >>> so open(False) is the same as open(0), and 0 is the file descriptor >>> associated to standard input. The program isn't hung, it's just waiting >>> for you to type some text >> >> That's interesting. Are there any more numbered pseudofiles? I suppose >> its mainly an excellent way to confuse people when you open(0).read(), >> but it would be interesting to know. > > Standard Unix behaviour dictates that 0 is stdin, 1 is stdout, and 2 is > stderr. So you can only read() from 0. > > Stefan Nitpicking, but open(1).read() and open(2).read() both succeed (for small values of success) the same way that open(0).read() does. Thanks for the advice, everybody. Geremy Condra
From: Giampaolo Rodolà on 12 May 2010 13:26 2010/5/12 Gabriel Genellina <gagsl-py2(a)yahoo.com.ar>: > open() in Python 3 does a lot of things; it's like a mix of codecs.open() + > builtin open() + os.fdopen() from 2.x all merged together. It does different > things depending on the type and quantity of its arguments, and even returns > objects of different types. > > In particular, open(some_integer) assumes some_integer is a file descriptor > and return some variant of file object using the given file descriptor. Interesting. I wasn't aware of this. Is it documented somewhere? --- Giampaolo http://code.google.com/p/pyftpdlib http://code.google.com/p/psutil
From: Kushal Kumaran on 12 May 2010 14:05 On Wed, May 12, 2010 at 10:56 PM, Giampaolo Rodolà <g.rodola(a)gmail.com> wrote: > 2010/5/12 Gabriel Genellina <gagsl-py2(a)yahoo.com.ar>: >> open() in Python 3 does a lot of things; it's like a mix of codecs.open() + >> builtin open() + os.fdopen() from 2.x all merged together. It does different >> things depending on the type and quantity of its arguments, and even returns >> objects of different types. >> >> In particular, open(some_integer) assumes some_integer is a file descriptor >> and return some variant of file object using the given file descriptor. > > Interesting. I wasn't aware of this. > Is it documented somewhere? > http://docs.python.org/py3k/library/functions.html#open -- regards, kushal
From: Terry Reedy on 12 May 2010 14:26 On 5/12/2010 1:26 PM, Giampaolo Rodolà wrote: > 2010/5/12 Gabriel Genellina<gagsl-py2(a)yahoo.com.ar>: >> open() in Python 3 does a lot of things; it's like a mix of codecs.open() + >> builtin open() + os.fdopen() from 2.x all merged together. It does different >> things depending on the type and quantity of its arguments, and even returns >> objects of different types. The change actually happened, according to 'What's new', in 2.6 when 'open' was made a synonym for the new io.open. >> In particular, open(some_integer) assumes some_integer is a file descriptor >> and return some variant of file object using the given file descriptor. > > Interesting. I wasn't aware of this. > Is it documented somewhere? Right where it should be, in the entry for 'open' under 'built-in functions': "file is either ... or an integer file descriptor of the file to be wrapped"
From: Dave Angel on 12 May 2010 14:36
Giampaolo Rodol� wrote: > 2010/5/12 Gabriel Genellina <gagsl-py2(a)yahoo.com.ar>: > >> open() in Python 3 does a lot of things; it's like a mix of codecs.open() + >> builtin open() + os.fdopen() from 2.x all merged together. It does different >> things depending on the type and quantity of its arguments, and even returns >> objects of different types. >> >> In particular, open(some_integer) assumes some_integer is a file descriptor >> and return some variant of file object using the given file descriptor. >> > > Interesting. I wasn't aware of this. > Is it documented somewhere? > > > http://docs.python.org/py3k/library/functions.html#open .... or an integer file descriptor of the file to be wrapped..... |