CODEWITHSUNDEEP
pythonlistmemory
secador de pelo
secador de pelo

Reputation: 699

Python: efficient way to store objects

I have to store 300+ Objects (users) in memory and get those users according to their ID. What is the most efficient way to do this?

Currently i'm storing the objects in a list, to get a user from the list i use this code:

[u for u in users if u.id == id]

This doesn't seem to be very efficient as i have to iterate over the whole list in the worst case.

Upvotes: 0

Views: 1985

Answers (2)

markcial
markcial

Reputation: 9323

Or use generators

instead of using a list comprehension dict use a tuple

(u for u in users if u.id == id)

EDIT

If the ids are unique my solution has nothing to do, the dict one is better, but it the issue is performance related the generator way has a good performance peak, like my performance test will show : 

import timeit

setup = """
from random import randint

class User:
    id = randint(0,10000)

users = [User() for _ in range(0,100)]

def generator_sample(users):
    final = (u for u in users if u.id == 100)

def list_sample(users):
    final = [u for u in users if u.id == 100]
"""

print timeit.timeit('generator_sample(users)', setup=setup)  # 0.413088083267
print timeit.timeit('list_sample(users)', setup=setup) # 4.37370610237

Upvotes: 2

shadab.tughlaq
shadab.tughlaq

Reputation: 454

Create a dict.

users = {}

add the values of each user as follows.

users[user_id] = "user_value"

You may just extract the particular record via the user id as

users[user_id]

You may store this either in mongo or store it using pickle.

Upvotes: 4

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