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Groups > comp.lang.python > #82175
| From | Terry Reedy <tjreedy@udel.edu> |
|---|---|
| Subject | Re: Python Iterables struggling using map() built-in |
| Date | 2014-12-09 00:03 -0500 |
| References | (2 earlier) <CALwzid=79=i3Sez3fQYV7xU2bEAL4_ohPqxhuYj59Y5ihXk1Zg@mail.gmail.com> <mailman.16685.1417976998.18130.python-list@python.org> <5484e3d8$0$13013$c3e8da3$5496439d@news.astraweb.com> <roy-3F4751.19122007122014@news.panix.com> <54866372$0$12991$c3e8da3$5496439d@news.astraweb.com> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.16758.1418101434.18130.python-list@python.org> (permalink) |
On 12/8/2014 9:50 PM, Steven D'Aprano wrote:
> Roy Smith wrote:
>
>> Chris Angelico wrote:
>>> def myzip(*args):
>>> iters = map(iter, args)
>>> while iters:
>>> res = [next(i) for i in iters]
>>> yield tuple(res)
>>
>> Ugh. When I see "while foo", my brain says, "OK, you're about to see a
>> loop which is controlled by the value of foo being changed inside the
>> loop".
>
> Yes. Me too. 99% of the time when you see "while foo", that's what you'll
> get, so it's the safe assumption. But it's only an assumption, not a
> requirement. When you read a bit more of the code and see that iters isn't
> being modified, your reaction ought to be closer "oh wow, that's neat"
To me it is a code smell. iters is empty if and only if args is empty.
If args is empty, iters should not be created.
if args:
iters = ...
while True
... (return on exception)
makes the logic clear.
--
Terry Jan Reedy
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Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-08 05:29 +1100
Re: Python Iterables struggling using map() built-in Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-08 10:33 +1100
Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-08 10:50 +1100
Re: Python Iterables struggling using map() built-in Roy Smith <roy@panix.com> - 2014-12-07 19:27 -0500
Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-08 11:35 +1100
Re: Python Iterables struggling using map() built-in Steven D'Aprano <steve@pearwood.info> - 2014-12-08 09:40 +0000
Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-08 20:50 +1100
Re: Python Iterables struggling using map() built-in Roy Smith <roy@panix.com> - 2014-12-08 19:02 -0500
Re: Python Iterables struggling using map() built-in Roy Smith <roy@panix.com> - 2014-12-07 19:12 -0500
Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-08 11:34 +1100
Re: Python Iterables struggling using map() built-in Roy Smith <roy@panix.com> - 2014-12-07 19:45 -0500
Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-08 12:00 +1100
Re: Python Iterables struggling using map() built-in MRAB <python@mrabarnett.plus.com> - 2014-12-08 03:09 +0000
Re: Python Iterables struggling using map() built-in Terry Reedy <tjreedy@udel.edu> - 2014-12-07 19:38 -0500
Re: Python Iterables struggling using map() built-in Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-12-08 18:06 +1300
Re: Python Iterables struggling using map() built-in Ned Batchelder <ned@nedbatchelder.com> - 2014-12-07 20:06 -0500
Re: Python Iterables struggling using map() built-in Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-09 13:50 +1100
Re: Python Iterables struggling using map() built-in Terry Reedy <tjreedy@udel.edu> - 2014-12-09 00:03 -0500
Re: Python Iterables struggling using map() built-in Steven D'Aprano <steve@pearwood.info> - 2014-12-09 06:40 +0000
Re: Python Iterables struggling using map() built-in Terry Reedy <tjreedy@udel.edu> - 2014-12-09 15:06 -0500
Re: Python Iterables struggling using map() built-in Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-10 11:10 +1100
Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-10 11:20 +1100
Re: Python Iterables struggling using map() built-in Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-10 00:24 +0000
Re: Python Iterables struggling using map() built-in Roy Smith <roy@panix.com> - 2014-12-09 21:44 -0500
Re: Python Iterables struggling using map() built-in Steven D'Aprano <steve@pearwood.info> - 2014-12-10 09:24 +0000
Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-10 20:32 +1100
Re: Python Iterables struggling using map() built-in Marko Rauhamaa <marko@pacujo.net> - 2014-12-10 12:58 +0200
Re: Python Iterables struggling using map() built-in Ian Kelly <ian.g.kelly@gmail.com> - 2014-12-10 09:46 -0700
Re: Python Iterables struggling using map() built-in Steven D'Aprano <steve@pearwood.info> - 2014-12-11 04:01 +0000
Re: Python Iterables struggling using map() built-in Ian Kelly <ian.g.kelly@gmail.com> - 2014-12-11 15:00 -0700
Re: Python Iterables struggling using map() built-in Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-12 10:28 +1100
Re: Python Iterables struggling using map() built-in Ian Kelly <ian.g.kelly@gmail.com> - 2014-12-11 16:57 -0700
Re: Python Iterables struggling using map() built-in Roy Smith <roy@panix.com> - 2014-12-11 20:55 -0500
Re: Python Iterables struggling using map() built-in Ian Kelly <ian.g.kelly@gmail.com> - 2014-12-12 00:36 -0700
Re: Python Iterables struggling using map() built-in Chris Angelico <rosuav@gmail.com> - 2014-12-12 11:44 +1100
Re: Python Iterables struggling using map() built-in Terry Reedy <tjreedy@udel.edu> - 2014-12-10 12:48 -0500
Re: Python Iterables struggling using map() built-in Ian Kelly <ian.g.kelly@gmail.com> - 2014-12-10 13:32 -0700
Re: Python Iterables struggling using map() built-in Terry Reedy <tjreedy@udel.edu> - 2014-12-10 23:17 -0500
Re: Python Iterables struggling using map() built-in Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-12-08 18:00 +1300
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