How to declare many variables?

You can use either a list of tuples or a dict. A simple solution to do it:

>>> import string
>>> letters = string.ascii_uppercase + string.ascii_lowercase + string.digits
>>> chars = dict.fromkeys(letters , 0)
>>> chars
>>> {...'a': 0, 'b': 0 ....}

To use list of tuples:

>>> list(chars.items())
>>> [...('a',0), ('b', 0)...]