method chains:
select
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 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)
def head(self, n):
return Clumper([self.blob[i] for i in range(n)])
def tail(self, n):
return Clumper([self.blob[-i] for i in range(1, n+1)])
def select(self, *keys):
return Clumper([{k: d[k] for k in keys} for d in self.blob])
We can now perform commands like;
(Clumper(poke_dict)
.keep(lambda d: 'Grass' in d['type'],
lambda d: d['hp'] < 60)
.select('name', 'hp')
.head(10)
.blob)
You may start to notice how flexible we now are because we can chain these commands together.
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