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Showing posts from June, 2014

A note on Python's __exit__() and errors

Python's context managers are a very neat way of handling code that needs a teardown once you are done. Python objects have do have a destructor method (__del__) called right before the last instance of the object is about to be destroyed. You can do a teardown there. However there is a lot of fine print to the __del__ method. A cleaner way of doing tear-downs is through Python's context manager, manifested as the with keyword.

class CrushMe: def __init__(self): self.f = open('test.txt', 'w') def foo(self, a, b): self.f.write(str(a - b)) def __enter__(self): return self def __exit__(self, exc_type, exc_val, exc_tb): self.f.close() return True with CrushMe() as c: c.foo(2, 3)
One thing that is important, and that got me just now, is error handling. I made the mistake of ignoring all those 'junk' arguments (exc_type, exc_val, exc_tb). I just skimmed the docs and what popped out is that you need to return True or False dep…

Feedburner and the fragmentation of google

Wordpress has a plugin for sending your post to twitter or linkedin (and linkedin has a builtin way of sending your updates to twitter) but I didn't see anything like that for blogger (except a G+ button for publicizing to that thriving community). Whenever I did a search I came up with some third party service. Finally I ran into Feedburner, which turns out to be Google's own service for publicizing things on social media. This just led me to an observation that google has so many services and they CAN talk to each other, but there are complicated layers between them.