Perf examples for ymanb

results.sh

$echo; for test in defaultdict setdefault check_in; do echo -n "${test}  "; python3 -m timeit -s "from test import test_${test} as test_func" "test_func()"; done

defaultdict  1000 loops, best of 3: 999 usec per loop
setdefault  1000 loops, best of 3: 1.89 msec per loop
check_in  1000 loops, best of 3: 1.27 msec per loop

test.py

from collections import defaultdict
from hashlib import md5

n_classes = 10
n_people = 10000
# use md5 to get some pseudorandomly ordered "names",
# for the sorting to be a factor
data = [(i%n_classes, md5(bytes(i)).hexdigest())
        for i in range(n_people)]

def test_defaultdict():
    roster = defaultdict(list)
    for class_, person in data:
        roster[class_].append(person)

def test_defaultdict_sorted():
    roster = defaultdict(list)
    for class_, person in data:
        roster[class_].append(person)
        roster[class_].sort()

def test_setdefault():
    roster = {}
    for class_, person in data:
        roster.setdefault(class_, []).append(person)

def test_setdefault_sorted():
    roster = {}
    for class_, person in data:
        this_class = roster.setdefault(class_, [])
        this_class.append(person)
        this_class.sort()

def test_check_in():
    roster = {}
    for class_, person in data:
        if class_ in roster:
            roster[class_].append(person)
        else:
            roster[class_] = [person]

def test_check_in_sorted():
    roster = {}
    for class_, person in data:
        if class_ in roster:
            roster[class_].append(person)
            roster[class_].sort()
        else:
            roster[class_] = [person]