using index() on multidimensional lists

Question

For a one dimensional list, the index of an item is found as follows:

 a_list = [\'a\', \'b\', \'new\', \'mpilgrim\', \'new\']
 a_list.index(\'mpilgrim\')


        

Answer 1

A multidimensional list is simply a list with more lists inside of it. So its indices would be lists themselves.

a = [[1, 2, 3], [2, 3, 4], [3, 4, 5]]
print a.index([2, 3, 4])
# prints 1

Answer 2

If you want to find the list that has an item, the simplest way to do it is:

i = 4
index = b_list[0].index( filter(lambda 1D_list: i in index , b_list[0]) )

Or if you know there are more than one matches for the item, then you can do:

i = 4
indexes = []
for match in filter(lambda 1D_list: i in list, b_list[0]):
    indexes.append(b_list[0].index(match))

None of this will raise any errors but they'll only work if there is no subarray. Go here for information about the functionality of filter.