Both the answers are good, but a little advice:
Tuples are immutable, which implies that they cannot be changed. So if you need to manipulate data, it is better to store data in a list, it will reduce unnecessary overhead.
In your case extract the data to a list, as shown by eumiro, and after modifying create a similar tuple of similar structure as answer given by Schoolboy.
Also as suggested using numpy array is a better option