Python- how do I use re to match a whole string [duplicate]

Anchor it to the start and end, and match one or more characters:

if re.match("^[a-zA-Z]+$", aString):

Here ^ anchors to the start of the string, $ to the end, and + makes sure you match 1 or more characters.

You’d be better off just using str.isalpha() instead though. No need to reach for the hefty regular expression hammer here:

>>> 'foobar'.isalpha()
True
>>> 'foobar42'.isalpha()
False
>>> ''.isalpha()
False