Re: [Python-ideas] Allow random.choice, random.sample to work on iterators

On Wed, Nov 30, 2016 at 11:57:46AM -0800, Chris Kaynor wrote: > Consider that this code will not produce the "correct" results (for a > reasonable definition of correct): > > a = (i for i in range(100)) # Pretend this does something more > interesting, and isn't a trivial generator - maybe a

Re: [Python-ideas] Allow random.choice, random.sample to work on iterators

On 2016-11-30 19:11, Chris Kaynor wrote: All that said, I would not be opposed to Python including a random.reservoir_choice (probably not the best name) function *in addition* to random.choice. The algorithm has its uses, but enough drawbacks and gotchas that it likely is not a good candidate

Re: [Python-ideas] Allow random.choice, random.sample to work on iterators

On Wed, Nov 30, 2016 at 12:21 PM, Bernardo Sulzbach wrote: > On 2016-11-30 17:57, Chris Kaynor wrote: >> >> On Wed, Nov 30, 2016 at 11:52 AM, Chris Kaynor >> wrote: >>> >>> There are also issues with how it should behave on iterables that >>>

Re: [Python-ideas] Allow random.choice, random.sample to work on iterators

Is the goal to allow them to consume a finite generator of *unknown* length (requires reservoir sampling https://en.wikipedia.org/wiki/Reservoir_sampling with N random calls, which seemed to be the rub before?) or just consume a generator with known length that's not indexable (a rare beast?).

Re: [Python-ideas] Allow random.choice, random.sample to work on iterators

On 2016-11-30 17:57, Chris Kaynor wrote: On Wed, Nov 30, 2016 at 11:52 AM, Chris Kaynor wrote: There are also issues with how it should behave on iterables that cannot be re-iterated (eg, random.choice will consume the iterator, and could only be called once safely).

Re: [Python-ideas] Allow random.choice, random.sample to work on iterators

On Wed, Nov 30, 2016 at 11:52 AM, Chris Kaynor wrote: > There are also issues with how it should behave on iterables that > cannot be re-iterated (eg, random.choice will consume the iterator, > and could only be called once safely). I meant to include a sample in my

Re: [Python-ideas] Allow random.choice, random.sample to work on iterators

This was also brought up back in April: https://mail.python.org/pipermail//python-ideas/2016-April/039707.html It got a few replies from Guido (https://mail.python.org/pipermail//python-ideas/2016-April/039713.html for one of them). It seems the idea got dropped due to problems with making it

Re: [Python-ideas] Allow random.choice, random.sample to work on iterators

On 2016-11-30 17:25, Random832 wrote: Currently these functions fail if the supplied object has no len(). There are algorithms for this task that can work on any finite iterator (for example, files as a stream of lines), and the functions could fall back to these if there is no len(). I like

Re: [Python-ideas] Add optional defaults to namedtuple

On 30 November 2016 at 13:09, Ethan Furman wrote: > But even more readable than that is using the NamedTuple class from my aenum > [3] library (and on SO as [3]): > > --> from aenum import NamedTuple > --> class Node(NamedTuple): > --> val = 0 > --> left = 1, 'previous

[Python-ideas] Allow random.choice, random.sample to work on iterators

Currently these functions fail if the supplied object has no len(). There are algorithms for this task that can work on any finite iterator (for example, files as a stream of lines), and the functions could fall back to these if there is no len(). ___

Re: [Python-ideas] Add optional defaults to namedtuple

On Wed, Nov 30, 2016 at 7:09 AM, Ethan Furman wrote: > On 11/30/2016 02:32 AM, Jelte Fennema wrote: > > It would be nice to have a supported way to add defaults to namedtuple, >> so the slightly hacky solution here does not have to be used: >>

Re: [Python-ideas] Add optional defaults to namedtuple

On 11/30/2016 02:32 AM, Jelte Fennema wrote: It would be nice to have a supported way to add defaults to namedtuple, so the slightly hacky solution here does not have to be used: http://stackoverflow.com/a/18348004/2570866 Actually, the solution right below it is better [1]: --> from

Re: [Python-ideas] Decorator to avoid a mistake

Hello, While I think this should not be "on by default", I don't see the harm in being able to opt-in to this behavior. I also figured spending a few minutes attempting to write this would be fun: https://gist.github.com/veloutin/2ec3e5246651f5de78442516d8e24fc1 François: sorry about the

Re: [Python-ideas] Better error messages [was: (no subject)]

On 30 November 2016 at 19:05, Paul Moore wrote: > On 30 November 2016 at 02:14, Stephen J. Turnbull > wrote: >> Wouldn't >> >> NameError: Python doesn't recognize the name "log". Perhaps >> you need to import the "math" module? >

Re: [Python-ideas] (no subject)

On 29/11/2016 20:09, Terry Reedy wrote: On 11/29/2016 11:32 AM, Rob Cliffe wrote: On 29/11/2016 04:58, victor rajewski wrote: Traceback (most recent call last): File "foo.py", line 2, in l[10]=14 IndexError: list assignment index out of range A better message might be: You

[Python-ideas] Add optional defaults to namedtuple

It would be nice to have a supported way to add defaults to namedtuple, so the slightly hacky solution here does not have to be used: http://stackoverflow.com/a/18348004/2570866 Jelte ___ Python-ideas mailing list Python-ideas@python.org

Re: [Python-ideas] Better error messages [was: (no subject)]

On 30 November 2016 at 02:14, Stephen J. Turnbull wrote: > How about: > > class Blog: > pass > > blog = get_blog_for_date(someday) > > logn = log(blog.size) > > NameError: Python doesn't recognize the function "log". Did you > mean