How to differentiate lines with one dot and two dot?

Question

I want to extract a specific part of a sentence. My problem is that I have a list of sentences that each have different formats. For instance:

X.y.com
 x.no
 x.com
 y.com
 z.co.uk
 s.com
 b.t.com

how can I split these lines based on the number of dots they have? If I want the second part of the sentence with two dots and the first part of the sentences with one dot

Answer 1

To anwser your question you could use count to count the number of times the '.' appears and then do whatever you need.

>>> 't.com'.count('.')
1
>>> 'x.t.com'.count('.')
2

You could use that in a loop:

for s in string_list:
    dots = s.count('.')
    if dots == 1:
        # do something here
    elif dots == 2:
        # do something else
    else:
        # another piece of code

More pythonic way to solve your problem:

def test_function(s):
    """
        >>> test_function('b.t.com')
        't'

        >>> test_function('x.no')
        'x'

        >>> test_function('z')
        'z'
    """
    actions = {0: lambda x: x
               1: lambda x: x.split('.')[0],
               2: lambda x: x.split('.')[1]}
    return actions[s.count('.')](s)