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... method chains.


Method chains are an amazing programming pattern if you're building an API that needs to be expressive in how it changes data. In this series of video's we will make a pandas-like datacontainer for lists of dictionaries.


Notes

This is the class that we had before.

class Clumper:
    def __init__(self, blob):
        self.blob = blob 

    def keep(self, func):
        return Clumper([d for d in self.blob if func(d)])

This is the class that we have now.

class Clumper:
    def __init__(self, blob):
        self.blob = blob 

    def keep(self, *funcs):
        data = self.blob 
        for func in funcs:
            data = [d for d in data if func(d)]
        return Clumper(data)

We can still perform commands in a chain.

(Clumper(poke_dict)
  .keep(lambda d: 'Grass' in d['type'])
  .keep(lambda d: d['hp'] < 60)
  .blob)

But we could also put all of our filtering functions into one keep call.

(Clumper(poke_dict)
  .keep(lambda d: 'Grass' in d['type'],
        lambda d: d['hp'] < 60)
  .blob)

Feedback? See an issue? Something unclear? Feel free to mention it here.

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