Because in general l[n] returns a sublist (possibly of length one), whereas l[[n]] returns an element: > lfile[2] [[1]] [1] “file2.xls” # returns SUBLIST of length one, not n’th ELEMENT > lfile[[2]] [1] “file2.xls” # returns ELEMENT From R intro manual: 6.1 Lists: It is very important to distinguish Lst[[1]] from Lst[1]. ‘[[…]]’ is the … Read more
Algorithm input = [2,5,1,4,7,3,1,2,3] output = [[]] for idx,val in enumerate(input): if idx > 0 and input[idx-1] > input[idx]: output.append([val]) else: output[-1].append(val) print output Output is [[2, 5], [1, 4, 7], [3], [1, 2, 3]] Explanation of the algorithm in words: Create an output list with an empty sublist. Enumerate over the input list. If … Read more
Try this, it splits the input list into sublists in the round-robin fashion you desire: def round_robin_sublists(l, n=4): lists = [[] for _ in range(n)] i = 0 for elem in l: lists[i].append(elem) i = (i + 1) % n return lists l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] sublist … Read more