Re: how to separate a list into two lists?
On Sun, 07 Aug 2011 01:07:00 +0800, smith jack wrote: > if a list L is composed with tuple consists of two elements, that is L = > [(a1, b1), (a2, b2) ... (an, bn)] > > is there any simple way to divide this list into two separate lists , > such that L1 = [a1, a2... an] > L2=[b1,b2 ... bn] > > i do not want to use loop, any methods to make this done? (x,y) = [ [z[i] for z in L] for i in range(len(L[0]))] x : ['a1', 'a2', 'an'] y : ['b1', 'b2', 'bn'] -- http://mail.python.org/mailman/listinfo/python-list
Re: how to separate a list into two lists?
On Sat, 06 Aug 2011 10:24:10 -0700, Emile van Sebille wrote:
> On 8/6/2011 10:07 AM smith jack said...
>> if a list L is composed with tuple consists of two elements, that is L
>> = [(a1, b1), (a2, b2) ... (an, bn)]
>>
>> is there any simple way to divide this list into two separate lists ,
>> such that L1 = [a1, a2... an]
>> L2=[b1,b2 ... bn]
>>
>>
> >>> L = [('a1', 'b1'), ('a2', 'b2'),('an', 'bn')] zip(*L)
> [('a1', 'a2', 'an'), ('b1', 'b2', 'bn')]
>
Nice. :) I forgot about zip, still learning Python myself.
I'll have to check up on the *L - is that a reference?
I know in Perl, you can assign the lhs to a list,
below works because there are exactly 2 items on the rhs.
Does Python have a catchall, or an ignore the rest?
Example, if L was a tuple that had 3 or more items,
the below lhs would fail. Is this possible in Python?
(X,Y) = zip(*L)
X
: ('a1', 'a2', 'an')
Y
: ('b1', 'b2', 'bn')
--
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Re: Python mascot proposal
richard wrote: > Having said that, don't forget that Python's name has *nothing to do > with snakes*. Please consider sticking to the original roots of the > language's name: Monty Python's Flying Circus. IIRC, Guido has said a > number of times that he's not fond of using a snake for logos. Some time ago while cruising a Barnes & Noble I found a Python book I hadn't seen before. I don't remember the title at the moment, and I don't have the book at hand, but the cover had a large python staring down at a small frightened rodent. When I went to check out, the person at the counter was a kind of frumpy librarian type. She looked at the cover and made some snide remark about frightening small children. I thought for a moment about trying to explain to her that the cover art was an inside joke on an inside joke. When I realized how far back I would have to go to unwind all the references, it just didn't seem worth the trouble. -- http://mail.python.org/mailman/listinfo/python-list
