Python: converting list of lists to tuples of tuples

Question

A Python newbie! I need help converting a list of lists tuples of tuples.

I want to call the append_as_tuples function, but every time I return it, it says
it can only concatenate lists (not tuples) to lists

Here is what I have so far:

def append_as_tuple(t, l):
    ''' Convert list l to a tuple and append it to tuple t as a single value '''
    return t[:] + (tuple(l),)  

def convert_lists(lol):
    t = []
    if type(lol) == a or type(lol) == tuple:
        return [convert_lists(lol) for i in t]
    return append_as_tuples(lol,a)

#- test harness#

a=[range(5), range(10,20), ['hello', 'goodbye']]  
print a  
print convert_lists(a)  
print convert_lists([])  

Solution 1

To convert list_of_lists to a tuple of tuples, use

tuple_of_tuples = tuple(tuple(x) for x in list_of_lists)

Solution 2

there is a python built in function: list and tuple

list( the tuple)...to conver tuple to list tuple( the list )....to convert list to tuple

Comments

[John Machin]

Your if type(lol) == a is quite wrong; it appears to work only because you have a global variable named a in your "test harness" and a is not a type instance ... so that test will be False. Without the global a, it would raise an exception.

[Leland Hepworth]

This will covert the outermost list to a tuple (or vice versa). However, the inner lists/tuples will remain as their original type.