References:
Code:
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python
Python sorted, itemgetter, stdin
I find it interesting how implementing a simple algorithm can teach you so many new things.
I was recently implementing the fractional knapsack problem
The interesting was – during implementation I got to learn some interesting things about Python.
- sorted
- items, iteritems
- itemgetter
- https://stackoverflow.com/questions/15371691/how-to-sort-a-dictionary-by-value-desc-then-by-key-asc
- cool trick to sort by combination of ascending and descending
- https://stackoverflow.com/questions/15371691/how-to-sort-a-dictionary-by-value-desc-then-by-key-asc
- sys.stdin
- EOF literal for Windows is Control+Z (not Control+D)
Code:
Python Break : Improve Your Python
I came across this very interesting series of blog posts. The authos (Jeff Knupp) discusses some nuances in Python
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Is Python call-by-value or call-by-reference? Neither.
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Improve Your Python: Python Classes and Object Oriented Programming
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Improve Your Python: Decorators Explained
There are a bunch of “Improve Your Python” articles in that blog. Check them out.
Code:
Python Class Attributes
I recently came across this interesting article on class attributes v/s instance attributes in Python.
References:
- https://www.toptal.com/python/python-class-attributes-an-overly-thorough-guide
- This actually let me to 2 other guides which are very interesting:
- https://pythonconquerstheuniverse.wordpress.com/2012/02/15/mutable-default-arguments/
- https://timothyawiseman.wordpress.com/2012/10/06/class-and-instance-variables-in-python-2-7/
- http://www2.lib.uchicago.edu/keith/courses/python/class/5/##classinst
- This is a very thorough guide. Highly recommended!
Code:
Factory Pattern in Python
I recently used the factory Pattern in Python.
It was a little surprising to me comparing typical usage of this pattern in C# v/s Python.
In particular, in C# you’s typically have an Interface defining the methods and then provide an implementation of these methods in the concrete classes.
In Python, there is no interface – In the example above I embed a static method in the base to select the appropriate derived class.
Temp files in Python.
Recently, I hit a nasty bug while working with temp files in Python.
The issue was manifesting itself in Windows. Interestingly I wasnt hitting it on Linux.
- As it so turns out I would have eventually hit it on Linux too.
The issue was because of a leaked file descriptor. The following link explains the issue
