Joh wrote:
>> def gen(iterable, start, end):
>>it = iter(iterable)
>>while True:
>>it, a = tee(it)
>>a = tuple(islice(a, end-1))
>>for sz in xrange(start, len(a)+1):
>>yield a[:sz]
>>it.next()
>>
>> if __name__ == "__main__":
>>print list(gen(range(1, 5), 2, 4))
>
> please, this one looks interes
hello,
thanks to all who replied to my post (2005-01-21) - (i can not post
inside the original thread as i get "Unable to retrieve message
[EMAIL PROTECTED]" from googlenews :(
> Do you mean:
> [1,2], [2,3], [3,4], [1,2,3], [2,3,4], [1,3,4]
> (E.g. all elements in the power set except the empty s
"Francis Girard" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
>If I understand correctly,
Almost...
> a "generator" produce something over which you can
> iterate with the help of an "iterator".
To be exact, the producer is a generator function, a function whose body
contains
On Sat, 2005-01-22 at 12:20 +0100, Alex Martelli wrote:
> Craig Ringer <[EMAIL PROTECTED]> wrote:
>
> > .>>> data = ''.join(x for x in infile)
>
> Maybe ''.join(infile) is a better way to express this functionality?
> Avoids 2.4 dependency and should be faster as well as more concise.
Thanks - f
Craig Ringer <[EMAIL PROTECTED]> wrote:
> .>>> data = ''.join(x for x in infile)
Maybe ''.join(infile) is a better way to express this functionality?
Avoids 2.4 dependency and should be faster as well as more concise.
> Might it be worth providing a way to have file objects seek back to the
> c
Francis Girard <[EMAIL PROTECTED]> wrote:
...
> > A 'def' of a function whose body uses 'yield', and in 2.4 the new genexp
> > construct.
>
> Ok. I guess I'll have to update to version 2.4 (from 2.3) to follow the
> discussion.
It's worth upgrading even just for the extra speed;-).
> > Since
On Sat, 2005-01-22 at 17:46 +0800, I wrote:
> I'd be interested to know if there's a better solution to this than:
>
> .>>> inpath = '/tmp/msg.eml'
> .>>> infile = open(inpath)
> .>>> initer = iter(infile)
> .>>> headers = []
> .>>> for line in initer:
> if not line.strip():
>
Le samedi 22 Janvier 2005 10:10, Alex Martelli a ÃcritÂ:
> Francis Girard <[EMAIL PROTECTED]> wrote:
>...
>
> > But besides the fact that generators are either produced with the new
> > "yield" reserved word or by defining the __new__ method in a class
> > definition, I don't know much about th
On Sat, 2005-01-22 at 10:10 +0100, Alex Martelli wrote:
> The answer for the current implementation, BTW, is "in between" -- some
> buffering, but bounded consumption of memory -- but whether that tidbit
> of pragmatics is part of the file specs, heh, that's anything but clear
> (just as for other
Nick Coghlan <[EMAIL PROTECTED]> wrote:
> 5. Several builtin functions return iterators rather than lists, specifically
> xrange(), enumerate() and reversed(). Other builtins that yield sequences
> (range(), sorted(), zip()) return lists.
Yes for enumerate and reversed, no for xrange:
>>> xx=xra
Francis Girard <[EMAIL PROTECTED]> wrote:
...
> But besides the fact that generators are either produced with the new "yield"
> reserved word or by defining the __new__ method in a class definition, I
> don't know much about them.
Having __new__ in a class definition has nothing much to do with
Francis Girard wrote:
In particular, I don't know what Python constructs does generate a generator.
I know this is now the case for reading lines in a file or with the new
"iterator" package. But what else ? Does Craig Ringer answer mean that list
comprehensions are lazy ? Where can I find a com
Thank you,
I immediately download version 2.4, switching from version 2.3.
Francis Girard
FRANCE
Le vendredi 21 Janvier 2005 17:34, Craig Ringer a ÃcritÂ:
> On Fri, 2005-01-21 at 16:54 +0100, Francis Girard wrote:
> > First, I think that you mean :
> >
> > consecutive_sets = [ x[offset:offset+su
On Fri, 2005-01-21 at 16:54 +0100, Francis Girard wrote:
> First, I think that you mean :
>
> consecutive_sets = [ x[offset:offset+subset_size]
> for subset_size in xrange(2, len(x))
> for offset in xrange(0, len(x) + 1 - subset_size)]
>
> (with square
Really, thank you Craig Ringer for your great answer.
> I'm afraid I can't help you with that. I tend to take the view that side
> effects in lazily executed code are a bad plan, and use lazy execution
> for things where there is no reason to care when the code is executed.
I completly agree wi
Le vendredi 21 Janvier 2005 16:06, Craig Ringer a ÃcritÂ:
> On Fri, 2005-01-21 at 22:38 +0800, Craig Ringer wrote:
> > consecutive_sets = ( x[offset:offset+subset_size]
> > for subset_size in xrange(2, len(x))
> > for offset in xrange(0, len(x) + 1 - subset
On Fri, 2005-01-21 at 16:05 +0100, Francis Girard wrote:
> I recently read David Mertz (IBM DeveloperWorks) about generators and
> got excited about using lazy constructs in my Python programming.
Speaking of totally great articles, and indirectly to lazyness (though
not lazyily evaluated construc
Joh wrote:
> i'm trying to understand how i could build following consecutive sets
> from a root one using generator :
>
> l = [1,2,3,4]
>
> would like to produce :
>
> [1,2], [2,3], [3,4], [1,2,3], [2,3,4]
>
> but unfortunately can not, i guess i can do it by using sub generator
> and maybe e
On Fri, 2005-01-21 at 22:38 +0800, Craig Ringer wrote:
> consecutive_sets = ( x[offset:offset+subset_size]
> for subset_size in xrange(2, len(x))
> for offset in xrange(0, len(x) + 1 - subset_size) )
Where 'x' is list to operate on, as I should've initial
Hi,
I recently read David Mertz (IBM DeveloperWorks) about generators and got
excited about using lazy constructs in my Python programming.
But besides the fact that generators are either produced with the new "yield"
reserved word or by defining the __new__ method in a class definition, I
don
On Fri, 2005-01-21 at 17:14 +0300, Denis S. Otkidach wrote:
> On 21 Jan 2005 05:58:03 -0800
> [EMAIL PROTECTED] (Joh) wrote:
>
> > i'm trying to understand how i could build following consecutive sets
> > from a root one using generator :
> >
> > l = [1,2,3,4]
> >
> > would like to produce :
> >
Joh wrote:
hello,
i'm trying to understand how i could build following consecutive sets
from a root one using generator :
l = [1,2,3,4]
would like to produce :
[1,2], [2,3], [3,4], [1,2,3], [2,3,4]
Do you mean:
[1,2], [2,3], [3,4], [1,2,3], [2,3,4], [1,3,4]
(E.g. all elements in the power set e
On 21 Jan 2005 05:58:03 -0800
[EMAIL PROTECTED] (Joh) wrote:
> i'm trying to understand how i could build following consecutive sets
> from a root one using generator :
>
> l = [1,2,3,4]
>
> would like to produce :
>
> [1,2], [2,3], [3,4], [1,2,3], [2,3,4]
>>> def consecutive_sets(l):
...
hello,
i'm trying to understand how i could build following consecutive sets
from a root one using generator :
l = [1,2,3,4]
would like to produce :
[1,2], [2,3], [3,4], [1,2,3], [2,3,4]
but unfortunately can not, i guess i can do it by using sub generator
and maybe enumerate, please if you h
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