Try this out, no regex needed:
pos_postfixes = ['k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y']
neg_postfixes = ['m', 'µ', 'n', 'p', 'f', 'a', 'z', 'y']
num_postfix = n[-1]
if num_postfix in pos_postfixes:
num = float(n[:-1])
num*=10**((pos_postfixes.index(num_postfix)+1)*3)
elif num_postfix in neg_postfixes:
num = float(n[:-1])
num*=10**(-(neg_postfixes.index(num_postfix)+1)*3)
else:
num = float(n)
print(num)
Another thing to note is that in python, it is more common to use underscore variable names than camelcasing, see the pep-8: http://www.python.org/dev/peps/pep-0008/