Use of enum and dictionary when search by value and search by key in equal proportions in python

Question

I am trying to have a map where i sometimes need to access key by value. But if i use dictionary, i have to iterate through the dictionary to get key using value

Color = {"RED" : 3,"BLACK" : 5, "GREEN" : 10}

for color in Color:
    if(Color[color] = 5):
        return color

But with enum i can easily find the key by value(aliasing)

class colors(Enum):
    RED = 3
    BLACK = 5
    GREEN = 10

colors(5).name

How is enum implemented as data structure that facilitates this? is it different from dict? and which method should i prefer for my problem?

What is best of both approaches in terms of space and time complexity?

Ironkey · Answer 1 · 2020-10-03T18:40:55.993

1

A dictionary uses keys and values, while an enum uses attributes of an object to store/access values. you can call the items from the dictionary like so:

color["BLACK"]

using dict:

colors = {"RED" : 3,"BLACK" : 5, "GREEN" : 10}
def getKey(dct,value):
     return [key for key in dct if (dct[key] == value)]

print(getKey(colors,5)[0])

in comparison to using an enum (as you already specified):

from enum import Enum
class colors(Enum):
    RED = 3
    BLACK = 5
    GREEN = 10

print(colors(5).name)

edited Oct 03 '20 at 18:40

answered Oct 03 '20 at 18:12

Ironkey

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reversing values and keys is not an option. so in this case should i use enum? – r2_d2 Oct 03 '20 at 18:29
how wouldn't it be an option? – Ironkey Oct 03 '20 at 18:31
Because search by key and value happens almost equal number of times in my problem – r2_d2 Oct 03 '20 at 18:36
I guess in that case, then using an enum could be somewhat preferable, ill edit my answer to show you a comparison. – Ironkey Oct 03 '20 at 18:39

Use of enum and dictionary when search by value and search by key in equal proportions in python

1 Answers1