[Python-ideas] Integrate some itertools into the Python syntax

Michel Desmoulin desmoulinmichel at gmail.com
Tue Mar 22 15:45:49 EDT 2016



Le 22/03/2016 20:26, Koos Zevenhoven a écrit :
> On Tue, Mar 22, 2016 at 9:10 PM, Koos Zevenhoven <k7hoven at gmail.com> wrote:
>> On Tue, Mar 22, 2016 at 8:41 PM, Ethan Furman <ethan at stoneleaf.us> wrote:
>>> On 03/22/2016 10:51 AM, Michel Desmoulin wrote:
>>>
>>>> def foo(p):
>>>>      with open(p) as f:
>>>>          def begin:
>>>>              return x == "BEGIN SECTION"
>>>>           def end:
>>>>              return x == "STOP"
>>>>          return f[begin, end][:10000]
>>>>
>>>> It's very clean, very convenient, very natural, and memory efficient.
>>>
>>>
>>> Except the 10,000 limit doesn't happen until /after/ the end block is
>>> reached -- which could be a million lines later.
>>
>>
>> if f[begin, end] is a generator, the 10000 limit may happen before the
>> end block is reached, which I think was the point.
>>
> 
> I should add, though, that the the function should probably return
> list(f[begin, end][:10000]) or something, before the file f is closed.
> 
>  - Koos

Yeah the semantic of my function is wrong. It should rather expect a
file like object as a parameter to avoid this bug.

Plus, the begin() and end() functions are actually syntax errors ^^

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