All you seem to need here is a list:
>>> l = ['a', 'd', 's', 't', 'd']
>>> l.insert(2, 'g')
>>> l
['a', 'd', 'g', 's', 't', 'd']
The second elements of your tuples are entirely redundant; the information they encode is already represented by the positions of the list elements. enumerate
may be useful here:
>>> for index, element in enumerate(l):
... print index, element
...
0 a
1 d
2 g
3 s
4 t
5 d