"Joel Koltner" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Is there an easy way to get a list comprehension to produce a flat list > of, say, [x,2*x] for each input argument? > > E.g., I'd like to do something like: > > [ [x,2*x] for x in range(4) ] > > ...and receive > > [ 0,0,1,2,2,4,3,6] > > ...but of course you really get a list of lists: > > [[0, 0], [1, 2], [2, 4], [3, 6]] > > I'm aware I can use any of the standard "flatten" bits of code to turn > this back into what I want, but I was hoping there's some way to avoid the > "lists of lists" generation in the first place? > > A slightly similar problem: If I want to "merge," say, list1=[1,2,3] with > list2=[4,5,6] to obtain [1,4,2,5,3,6], is there some clever way with "zip" > to do so? > > Thanks, > ---Joel >
i figured out a solution sum([x,2*x] for x in range(4)],[]) #not tested sum(zip(list1,list2),()) #not tested (you did say you knew of ways to flatten, but i dunno if you knew of that way or not) as an aside, i wish that sum didn't have to take the second parameter. it's kind of superfluous. it can just use the first item as the initial value instead of 0 when no initial value is specified. it would be a little complex to do without putting a conditional in your main loop and slowing it down, but it could be done. -- http://mail.python.org/mailman/listinfo/python-list
