Filtering Dictionary in Python
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from typing import Dict | |
# Helper function to generate dict object | |
def get_menu() -> Dict[str, dict]: | |
return { | |
"TIMMY_BLACK": { | |
"item": "Timmy's Coffee Barista's Black", | |
"sugar_free": True, | |
"with_milk": False, | |
}, | |
"TIMMY_LATTE": { | |
"item": "Timmy's Coffee Latte", | |
"sugar_free": True, | |
"with_milk": False, | |
}, | |
"TIMMY_SWEETENED_LATTE": { | |
"item": "Timmy's Coffee Latte - Sweetened", | |
"sugar_free": True, | |
"with_milk": True, | |
}, | |
"TIMMY_SIGNATURE_CARAMEL": { | |
"item": "Timmy's Signature - Caramel Latte", | |
"sugar_free": None, # Unknown | |
"with_milk": True, | |
} | |
} | |
# Our dict subclass | |
class FilterableDict(dict): | |
def __init__(self, *args, **kwargs): | |
dict.__init__(self, *args, **kwargs) | |
def filter(self, predicate): | |
key_copy = tuple(self.keys()) | |
for k in key_copy: | |
if predicate(k, self.get(k)): | |
del self[k] | |
return self | |
def __repr__(self): | |
return "FilterableDict({})".format(super().__repr__()) | |
coffees = FilterableDict(get_menu()) | |
coffees # FilterableDict({...}) | |
len(coffees) # 4 | |
sugar_free_filter = lambda _, v: not v["sugar_free"] | |
coffees.filter(sugar_free_filter) | |
len(coffees) # 3 |
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