On Oct 17, 4:41 pm, Carsten Haese <[EMAIL PROTECTED]> wrote: > On Wed, 2007-10-17 at 20:27 +0000, Debajit Adhikary wrote: > > I have two lists: > > > a = [1, 2, 3] > > b = [4, 5, 6] > > > What I'd like to do is append all of the elements of b at the end of > > a, so that a looks like: > > > a = [1, 2, 3, 4, 5, 6] > > > I can do this using > > > map(a.append, b) > > > How do I do this using a list comprehension? > > You don't. > > > (In general, is using a list comprehension preferable (or more > > "pythonic") as opposed to using map / filter etc.?) > > In general, a list comprehension is more Pythonic nowadays, but in your > particular case the answer is neither map nor a list comprehension, it's > this: > > a += b > > HTH, > > -- > Carsten Haesehttp://informixdb.sourceforge.net
Thanks a ton :) What in general is a good way to learn about little things like these? (I'm fairly new to the language) A google search for 'python list methods" did not turn up the + operator anywhere for me. Where could I find the official documentation for built in structures like the list? (I just noticed that the + operator for lists is mentioned in Beazley's Python Essential Reference -- in the opening pages, which I didn't look at when I was writing the earlier code.) How does "a.extend(b)" compare with "a += b" when it comes to performance? Does a + b create a completely new list that it assigns back to a? If so, a.extend(b) would seem to be faster. How could I verify things like these? -- http://mail.python.org/mailman/listinfo/python-list
