1024m...@gmail.com wrote: > i have the following matrix: > catch = [['fc', 2, 12, 2], > ['abcd', 1, 2, 0], > ['ab', 1, 0, 0], > ['cf', 1, 13, 0], > ['fc', 1, 14, 0], > ['f', 1, 11, 0]] > > and i want this matrix to be ordered by the third columns firstly, when > the values of the third column are equals, by the second column. > > i just used > catch.sort(key=lambda x: x[3]) > to sort the matrix by third column
You can use catch.sort(key=lambda x: (x[3], x[2])) or, because sort() is "stable" do it in two steps catch.sort(key=lambda x: x[2]) # least significant sort first catch.sort(key=lambda x: x[3]) Instead of the lambda you can use operator.itemgetter(): >>> from pprint import pprint >>> from operator import itemgetter >>> catch = [['fc', 2, 12, 2], ... ['abcd', 1, 2, 0], ... ['ab', 1, 0, 0], ... ['cf', 1, 13, 0], ... ['fc', 1, 14, 0], ... ['f', 1, 11, 0]] >>> catch.sort(key=itemgetter(3, 2)) >>> pprint(catch) [['ab', 1, 0, 0], ['abcd', 1, 2, 0], ['f', 1, 11, 0], ['cf', 1, 13, 0], ['fc', 1, 14, 0], ['fc', 2, 12, 2]] -- https://mail.python.org/mailman/listinfo/python-list
