Titlecasing a string with exceptions

Is there a standard way in Python to titlecase a string (i.e. words start with uppercase characters, all remaining cased characters have lowercase) but leaving articles like and, in, and of lowercased?

Answer

There are a few problems with this. If you use split and join, some white space characters will be ignored. The built-in capitalize and title methods do not ignore white space.

>>> 'There     is a way'.title()
'There     Is A Way'

If a sentence starts with an article, you do not want the first word of a title in lowercase.

Keeping these in mind:

import re 
def title_except(s, exceptions):
    word_list = re.split(' ', s)       # re.split behaves as expected
    final = [word_list[0].capitalize()]
    for word in word_list[1:]:
        final.append(word if word in exceptions else word.capitalize())
    return " ".join(final)

articles = ['a', 'an', 'of', 'the', 'is']
print title_except('there is a    way', articles)
# There is a    Way
print title_except('a whim   of an elephant', articles)
# A Whim   of an Elephant