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Groups > comp.lang.python > #79714
| From | Dan Sommers <dan@tombstonezero.net> |
|---|---|
| Newsgroups | comp.lang.python |
| Subject | Re: Status of side-effecting functions in python |
| Date | 2014-10-26 13:41 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <m2itm2$l5r$1@dont-email.me> (permalink) |
| References | <c5e3a7e7-5997-47ee-8e81-759f2342c87a@googlegroups.com> <mailman.15174.1414273325.18130.python-list@python.org> <438d510f-05ae-47dd-bcda-42a8b777c99b@googlegroups.com> |
On Sun, 26 Oct 2014 00:45:49 -0700, wxjmfauth wrote:
> Ditto for <fileobj>.write(). Why should it return "something" ?
>
>>>> with open('z.txt', 'w') as f:
> ... f.write('abc')
> ...
> 3
OTOH, why shouldn't it return something? In this case, it returns the
length of the string written. This value is analogous to the value
returned by the underlying OS function (at least on a POSIX-like system,
where write(2) returns the number of bytes written). This value can be
useful for detecting when things have gone wrong; e.g., disk full,
network down, pipe broken, etc. Practicality definitely beats purity.
At one time, on a huge project, millions of lines of C and assembly
code, we had a local guideline *not* to write void functions. The idea
was to return something that might be useful later, even if it seemed
unlikely now. A simple success flag was sufficient; as functions grew,
often did their failure modes.
Dan
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Status of side-effecting functions in python Rustom Mody <rustompmody@gmail.com> - 2014-10-25 10:27 -0700
Re: Status of side-effecting functions in python Wolfgang Maier <wolfgang.maier@biologie.uni-freiburg.de> - 2014-10-25 23:41 +0200
Re: Status of side-effecting functions in python Dan Sommers <dan@tombstonezero.net> - 2014-10-25 22:22 +0000
Re: Status of side-effecting functions in python Terry Reedy <tjreedy@udel.edu> - 2014-10-25 18:53 -0400
Re: Status of side-effecting functions in python wxjmfauth@gmail.com - 2014-10-26 00:45 -0700
Re: Status of side-effecting functions in python Dan Sommers <dan@tombstonezero.net> - 2014-10-26 13:41 +0000
Re: Status of side-effecting functions in python Rustom Mody <rustompmody@gmail.com> - 2014-10-26 07:53 -0700
Re: Status of side-effecting functions in python wxjmfauth@gmail.com - 2014-10-26 09:26 -0700
Re: Status of side-effecting functions in python Marko Rauhamaa <marko@pacujo.net> - 2014-10-26 18:50 +0200
Re: Status of side-effecting functions in python Roy Smith <roy@panix.com> - 2014-10-26 17:56 -0400
Re: Status of side-effecting functions in python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-10-27 22:30 +1100
Re: Status of side-effecting functions in python Chris Angelico <rosuav@gmail.com> - 2014-10-27 22:44 +1100
Re: Status of side-effecting functions in python Roy Smith <roy@panix.com> - 2014-10-27 09:28 -0400
Re: Status of side-effecting functions in python Grant Edwards <invalid@invalid.invalid> - 2014-10-27 14:45 +0000
Re: Status of side-effecting functions in python Marko Rauhamaa <marko@pacujo.net> - 2014-10-27 17:14 +0200
Re: Status of side-effecting functions in python Nobody <nobody@nowhere.invalid> - 2014-10-28 03:52 +0000
Re: Status of side-effecting functions in python Marko Rauhamaa <marko@pacujo.net> - 2014-10-28 11:07 +0200
Re: Status of side-effecting functions in python Marko Rauhamaa <marko@pacujo.net> - 2014-10-28 11:10 +0200
.write() behavior Alan Bawden <alan@scooby-doo.csail.mit.edu> - 2014-10-29 01:06 -0400
Re: .write() behavior Marko Rauhamaa <marko@pacujo.net> - 2014-10-29 08:00 +0200
Re: .write() behavior Alan Bawden <alan@scooby-doo.csail.mit.edu> - 2014-10-31 16:32 -0400
Re: Status of side-effecting functions in python Grant Edwards <invalid@invalid.invalid> - 2014-10-27 14:22 +0000
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