Hello there, let's suppose I have the following matrix:
mat = [[1,2,3], [3,2,4], [7,8,9], [6,2,9]] where [.. , .. , ..] are the rows. I am interested into getting the "row index" of all the matrix rows where a certain number occurs. For example for 9 I should get 2 and 3 (starting from 0). For 10 I should get an error msg (item not found) and handle it. How to get the"row indexes" of found items? In practice I am looking for an equivalent to "list.index(x)" for the case "lists of lists" Many Thanks! Alex PS: this is just a simplified example, but I have actually to deal with large matrices [~500000 * 4] -- http://mail.python.org/mailman/listinfo/python-list
