Tuesday, April 17, 2012

Some Python

The other day, I was trying to flag a posted (to the Redis server for quick lookup) recommendation from a dictionary of recommendations. Then the next round, I could do some weighted random sampling among the unposted ones, without actually going through the entire recommendation calculations. Anyway, it's a little bit tricky to neatly flag a 'used' recommendation in a python dictionary. Fortunately, someone has already provided a solution. I'd like to borrow it over for quick references.
>>> x = {'a':1, 'b': 2}
>>> y = {'b':10, 'c': 11}
>>> z = dict(x.items() + y.items())
>>> z
{'a': 1, 'c': 11, 'b': 10}

b's vlaue is properly overwritten by the value in second dictionary. In Python 3, this is suggested
>>> z = dict(list(x.items()) + list(y.items()))
>>> z
{'a': 1, 'c': 11, 'b': 10}

And I saw a cool post about using python's map, reduce, filter function to a dictionary. Once again, something could be cleanly and flexibly accomplished. Python is such a beautiful language.

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