Re: Conversion of List of Tuples
On 12/03/2012 11:58 AM, subhabangal...@gmail.com wrote: [(1,2), (3,4)] L=[(1,2), (3,4)] [b for a in L for b in a] [1, 2, 3, 4] -- Dr. Gary Herron Department of Computer Science DigiPen Institute of Technology (425) 895-4418 -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
Am 03.12.2012 20:58, schrieb subhabangal...@gmail.com: Dear Group, I have a tuple of list as, tup_list=[(1,2), (3,4)] Now if I want to covert as a simple list, list=[1,2,3,4] how may I do that? Another approach that has not yet been mentioned here: a=[(1,2), (3,4)] b=[] map(b.extend, a) [None, None] b [1, 2, 3, 4] map returns [None, None] because extend returns nothing, but now b==[1,2,3,4]. There are more ways: from operator import add reduce(add, a) (1, 2, 3, 4) or reduce(operator.add, (list(t) for t in a)) [1, 2, 3, 4] I didn't do any performance testing, i guess the first one should be about as fast es the for-loop approach with .extend() and the other two might be quite slow. Although this only really matters if you have large lists. Greetings -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
On 4/12/12 10:44:32, Alexander Blinne wrote: Am 03.12.2012 20:58, schrieb subhabangal...@gmail.com: Dear Group, I have a tuple of list as, tup_list=[(1,2), (3,4)] Now if I want to covert as a simple list, list=[1,2,3,4] how may I do that? Another approach that has not yet been mentioned here: a=[(1,2), (3,4)] b=[] map(b.extend, a) [None, None] b [1, 2, 3, 4] map returns [None, None] because extend returns nothing, but now b==[1,2,3,4]. It's considered bad style to use map it you don't want the list it produces. There are more ways: from operator import add reduce(add, a) (1, 2, 3, 4) There's a built-in that does reduce(operator.add; it's called sum: sum(a, ()) (1, 2, 3, 4) or reduce(operator.add, (list(t) for t in a)) [1, 2, 3, 4] This is a valid use case for the map operator: sum(map(list, a), []) [1, 2, 3, 4] I didn't do any performance testing, i guess the first one should be about as fast as the for-loop approach with .extend() and the other two might be quite slow. Although this only really matters if you have large lists. Hope this helps, -- HansM -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
On 2012-12-04, Hans Mulder han...@xs4all.nl wrote: It's considered bad style to use map it you don't want the list it produces. There are more ways: from operator import add reduce(add, a) (1, 2, 3, 4) There's a built-in that does reduce(operator.add; it's called sum: sum(a, ()) (1, 2, 3, 4) I thought that sort of thing would cause a warning. Maybe it's only for lists. Here's the recipe from the itertools documentation: def flatten(listOfLists): Flatten one level of nesting return chain.from_iterable(listOfLists) -- Neil Cerutti -- http://mail.python.org/mailman/listinfo/python-list
Conversion of List of Tuples
Dear Group, I have a tuple of list as, tup_list=[(1,2), (3,4)] Now if I want to covert as a simple list, list=[1,2,3,4] how may I do that? If any one can kindly suggest? Googling didn't help much. Regards, Subhabrata. -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
In 6049bc85-6f8e-429b-a855-ecef47a9d...@googlegroups.com subhabangal...@gmail.com writes: Dear Group, I have a tuple of list as, tup_list=[(1,2), (3,4)] Now if I want to covert as a simple list, list=[1,2,3,4] how may I do that? new_list = [] for t in tup_list: for item in t: new_list.append(item) -- John Gordon A is for Amy, who fell down the stairs gor...@panix.com B is for Basil, assaulted by bears -- Edward Gorey, The Gashlycrumb Tinies -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
On Mon, Dec 3, 2012 at 11:58 AM, subhabangal...@gmail.com wrote: Dear Group, I have a tuple of list as, tup_list=[(1,2), (3,4)] Now if I want to covert as a simple list, list=[1,2,3,4] how may I do that? If any one can kindly suggest? Googling didn't help much. If you know they are always exactly two levels deep, you can use nested loops (in comprehension form): [item for tuple_ in list_ for item in tuple_] That could also be written how John recommended, in three lines. Regards, Subhabrata. -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
On 2012-12-03 20:04, John Gordon wrote: In 6049bc85-6f8e-429b-a855-ecef47a9d...@googlegroups.com subhabangal...@gmail.com writes: Dear Group, I have a tuple of list as, tup_list=[(1,2), (3,4)] Now if I want to covert as a simple list, list=[1,2,3,4] how may I do that? new_list = [] for t in tup_list: for item in t: new_list.append(item) Or you could use .extend: new_list = [] for t in tup_list: new_list.extend(t) -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
On Tue, Dec 4, 2012 at 7:04 AM, John Gordon gor...@panix.com wrote: In 6049bc85-6f8e-429b-a855-ecef47a9d...@googlegroups.com subhabangal...@gmail.com writes: Dear Group, I have a tuple of list as, tup_list=[(1,2), (3,4)] Now if I want to covert as a simple list, list=[1,2,3,4] how may I do that? new_list = [] for t in tup_list: for item in t: new_list.append(item) Which can be written more succintly as: new_list = [] for t in tup_list: new_list.extend(t) In more general terms, what you're looking to do here is *flatten* your structure. Not sure if that would have helped in the web search that you doubtless did before asking this question. :) ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
On Tuesday, December 4, 2012 1:28:17 AM UTC+5:30, subhaba...@gmail.com wrote: Dear Group, I have a tuple of list as, tup_list=[(1,2), (3,4)] Now if I want to covert as a simple list, list=[1,2,3,4] how may I do that? If any one can kindly suggest? Googling didn't help much. Regards, Subhabrata. Thanks. But I am not getting the counter 5posts 0 views...if moderator can please check the issue. -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
In e89cddcc-71ab-4223-b66e-8c853634a...@googlegroups.com subhabangal...@gmail.com writes: Thanks. But I am not getting the counter 5posts 0 views...if moderator can please check the issue. I logged in via Google Groups and all the replies were present. What is your question? (This group is not moderated.) -- John Gordon A is for Amy, who fell down the stairs gor...@panix.com B is for Basil, assaulted by bears -- Edward Gorey, The Gashlycrumb Tinies -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
On Mon, 03 Dec 2012 13:14:19 -0800, subhabangalore wrote: Thanks. But I am not getting the counter 5posts 0 views...if moderator can please check the issue. What counter are you talking about? This is an email mailing list, also copied to the Usenet newsgroup comp.lang.python, and mirrored on other places including gmane and various web sites. Neither email nor Usenet include counters, so you will have to explain what you are talking about. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Conversion of List of Tuples
On Mon, 03 Dec 2012 22:11:40 +, Steven D'Aprano wrote: On Mon, 03 Dec 2012 13:14:19 -0800, subhabangalore wrote: Thanks. But I am not getting the counter 5posts 0 views...if moderator can please check the issue. What counter are you talking about? This is an email mailing list, also copied to the Usenet newsgroup comp.lang.python, and mirrored on other places including gmane and various web sites. Neither email nor Usenet include counters, so you will have to explain what you are talking about. Doubtless he is talking about G**gle Groups, since I don't see his posts anyway. -- http://mail.python.org/mailman/listinfo/python-list
