Removing everything except letters and spaces from string in Python3.3

Question

I have this example string: happy t00 go 129.129 and I want to keep only the spaces and letters. All I have been able to come up with so far that is pretty efficient is:

print(re.sub("\d", "", 'happy t00 go 129.129'.replace('.', '')))

but it is only specific to my example string. How can remove all characters other than letters and spaces?

Answer 1

whitelist = set('abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ')
myStr = "happy t00 go 129.129$%^&*("
answer = ''.join(filter(whitelist.__contains__, myStr))

Output:

>>> answer
'happy t go '