Re: [Python-Dev] itertools.chain should take an iterable ?
Jack Diederich wrote:
On Thu, Sep 01, 2005 at 07:58:40PM +0200, Paolino wrote:
Working on a tree library I've found myself writing
itertools.chain(*[child.method() for child in self]).
Well this happened after I tried instinctively
itertools.chain(child.method() for child in self).
Is there a reason for this signature ?
This is more suited to comp.lang.python
Why ? I'm not asking for help ,I'm asking why itertools library is
implemented like that and if it is possible to clean it.
Consider the below examples (and remember that strings are iterable)
import itertools as it
list(it.chain('ABC', 'XYZ'))
['A', 'B', 'C', 'X', 'Y', 'Z']
list(it.chain(['ABC', 'XYZ']))
['ABC', 'XYZ']
list(it.chain(['ABC'], ['XYZ']))
['ABC', 'XYZ']
What if I want to chain an infinite list of iterables?
Shouldn't itertools.chain be built to handle that?
I don't think it is a problem to accept only the second case you paste
and produce TypeError on the others.
Hope this explains and to get other reasons.
Regards
Paolino
Hope that helps,
-jackdied
___
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
http://mail.python.org/mailman/options/python-dev/paolo_veronelli%40libero.it
___
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] itertools.chain should take an iterable ?
[Paolino] Well this happened after I tried instinctively itertools.chain(child.method() for child in self). As Jack's note points out, your proposed signature is incompatible with the one we have now. I recommend creating your own version: def paolino_chain(iterables): for it in iterables: for element in it: yield element list(chain(c+c for c in string.ascii_uppercase)) ['A', 'A', 'B', 'B', 'C', 'C', 'D', 'D', 'E', 'E', 'F', 'F', 'G', 'G', 'H', 'H', 'I', 'I', 'J', 'J', 'K', 'K', 'L', 'L', 'M', 'M', 'N', 'N', 'O', 'O', 'P', 'P', 'Q', 'Q', 'R', 'R', 'S', 'S', 'T', 'T', 'U', 'U', 'V', 'V', 'W', 'W', 'X', 'X', 'Y', 'Y', 'Z', 'Z'] Is there a reason for this signature ? It was handy for the use cases I had in mind when creating the function. Also it was styled after a version in another language where it had proven successful. This is more suited to comp.lang.python Why ? I'm not asking for help ,I'm asking why itertools library is implemented like that and if it is possible to clean it. The newsgroup would have guided you to the solution listed above. If you want to request a new feature, please use SourceForge. Raymond ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] itertools.chain should take an iterable ?
Christos Georgiou wrote: Paolino [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] What if I want to chain an infinite list of iterables? Shouldn't itertools.chain be built to handle that? Raymond already suggested a four-line function that does exactly that. Create your own personal-library modules containing the functions you find useful as building blocks, and when you have a large sw base using them, present your building blocks along with their use cases as arguments for inclusion in the standard library. I don't think it is a problem to accept only the second case you paste and produce TypeError on the others. It would break compatibility with the current uses of itertools.chain . I like it (and have used it) as it is. I see ,I just thought itertools was young and important enough to be investigated and eventually changed, but probably this is not the place to talk about that.I will submit the feature request to SF. I must add that the inverse story would have been def handy_chain(*args): return itertools.chain(iter(args)) a two-line function (ex lambda). Generally speaking, having a star-signature in a base library function is not a good choice. This is a proof of a case. Thanks all and have a nice summer. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] itertools.chain should take an iterable ?
Working on a tree library I've found myself writing itertools.chain(*[child.method() for child in self]). Well this happened after I tried instinctively itertools.chain(child.method() for child in self). Is there a reason for this signature ? Regards paolino ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] itertools.chain should take an iterable ?
On Thu, Sep 01, 2005 at 07:58:40PM +0200, Paolino wrote:
Working on a tree library I've found myself writing
itertools.chain(*[child.method() for child in self]).
Well this happened after I tried instinctively
itertools.chain(child.method() for child in self).
Is there a reason for this signature ?
This is more suited to comp.lang.python
Consider the below examples (and remember that strings are iterable)
import itertools as it
list(it.chain('ABC', 'XYZ'))
['A', 'B', 'C', 'X', 'Y', 'Z']
list(it.chain(['ABC', 'XYZ']))
['ABC', 'XYZ']
list(it.chain(['ABC'], ['XYZ']))
['ABC', 'XYZ']
Hope that helps,
-jackdied
___
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
