How to find the longest word with python?

How can I use python to find the longest word from a set of words? I can find the first word like this:

'a aa aaa aa'[:'a aa aaa aa'.find(' ',1,10)]

'a'

rfind is another subset

'a aa aaa aa'[:'a aa aaa aa'.rfind(' ',1,10)]

'a aa aaa'

Answer

If I understand your question correctly:

>>> s = "a aa aaa aa"
>>> max(s.split(), key=len)
'aaa'

split() splits the string into words (seperated by whitespace); max() finds the largest element using the builtin len() function, i.e. the string length, as the key to find out what “largest” means.