Experience with Python...

Last weekend I attended 10th Edition of PyCon India in Hyderabad. I had started using python seriously around 2009 when first PyCon India happened. During first edition entire FOSSEE team was participating and while I was getting better understanding of using Python we as team were also conducting introductory workshops around it. We were pitching python really hard, our workshops content had all cool features which python was offering and how coding becomes so easy compared to Matlab or C or other languages being used in Indian colleges. Back then I personally also believed in what I was preaching, but today, I have my doubts.

In latest Pycon edition, opening keynote was given by Armin, and his talk was around future of Python, given that Guido is removing himself from decision process. One point which was covered in the talk was about how there are guidelines via certain PEPs, but language by itself never enforces them. I have personally used flake8 to adhere to a certain formatting, but again, its an external tool and still not part of standard libraries. The talk, bubbled up some of my recent doubts on what is right approach of doing something. During first PyCon, if I remember correctly, we had zen of python printed on the TShirts which we were handing out, and I very clearly remembered the line:

There should be one– and preferably only one –obvious way to do it.

Here is a small example on how try, except leaves me confused on what would be right approach to use them. I am quoting from a StackOverflow conversation, which goes like:

In the Python world, using exceptions for flow control is common and normal.

So, I have a dictionary and I want to use one of its key and I can do something like:

try:
    uri = station['uri']
except KeyError:
    return

python dict supports a get which can return default value in case key is missing. So using that we can also handle above situation using a if else block:

if station.get('uri'):
    uri = station.get('uri')
else:
    return

#################### OR ####################
uri = station.get('uri')
if not uri:
    return

#################### OR ####################
if 'uri' in station:
    uri = station['uri']
else:
    return

I already feel a bit lost or conflicted, if I follow quote from stackoverflow, first method is and should be the way things need to be done. But I have used both methods in different situation, and that is conflicting to the zen ideology quoted above.

Furthermore, I have tried to use try, except and limit the scope of the block to minimum lines of code instead of stretching it to complete function or logic, but there, handling return for every exception, made the code hard to follow. For multiple exit points I make sure that at every exit, number of variables returned are same, I write unittests to confirm that it is the case, all in place, tests are passing, and at the end, code doesn't look clean anymore, I feel that I am violating the first line of zen:

Beautiful is better than ugly.

Personally, I think there is lot of room to get better at this, these are very fundamental concepts which shouldn't be hard or confusing. From here on, I will be looking out for some pattern across popular libraries and their implementation, understand their approach and get clarity on which methodology is better suited for which situation.