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Cómo escribir código Python eficiente

Logan Thomas

Scientific Software Technical Trainer, Enthought

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Entiende qué hace cada iteración del bucle
Mueve los cálculos de una sola vez fuera (arriba) del bucle
Usa conversiones holísticas fuera (abajo) del bucle
Todo lo que se haga una vez debe ir fuera del bucle

Mueve cálculos por encima del bucle

import numpy as np

names = ['Absol', 'Aron', 'Jynx', 'Natu', 'Onix']
attacks = np.array([130, 70, 50, 50, 45])

for pokemon,attack in zip(names, attacks):

    total_attack_avg = attacks.mean()

    if attack > total_attack_avg:
        print(
            "{}'s attack: {} > average: {}!"
            .format(pokemon, attack, total_attack_avg)
        )

Absol's attack: 130 > average: 69.0!
Aron's attack: 70 > average: 69.0!

import numpy as np

names = ['Absol', 'Aron', 'Jynx', 'Natu', 'Onix']
attacks = np.array([130, 70, 50, 50, 45])

# Calculate total average once (outside the loop)
total_attack_avg = attacks.mean()

for pokemon,attack in zip(names, attacks):

    if attack > total_attack_avg:
        print(
            "{}'s attack: {} > average: {}!"
            .format(pokemon, attack, total_attack_avg)
        )

Absol's attack: 130 > average: 69.0!
Aron's attack: 70 > average: 69.0!

Mueve cálculos por encima del bucle

%%timeit
for pokemon,attack in zip(names, attacks):

    total_attack_avg = attacks.mean()

    if attack > total_attack_avg:
        print(
            "{}'s attack: {} > average: {}!"
            .format(pokemon, attack, total_attack_avg)
        )

74.9 µs ± 3.42 µs per loop (mean ± std. dev. of 7 runs, 10000 loops each)

Mueve cálculos por encima del bucle

%%timeit
# Calculate total average once (outside the loop)
total_attack_avg = attacks.mean()

for pokemon,attack in zip(names, attacks):

    if attack > total_attack_avg:
        print(
            "{}'s attack: {} > average: {}!"
            .format(pokemon, attack, total_attack_avg)
        )

37.5 µs ± 281 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)

Usa conversiones holísticas

names = ['Pikachu', 'Squirtle', 'Articuno', ...]
legend_status = [False, False, True, ...]
generations = [1, 1, 1, ...]

poke_data = []
for poke_tuple in zip(names, legend_status, generations):

    poke_list = list(poke_tuple)

    poke_data.append(poke_list)

print(poke_data)

[['Pikachu', False, 1], ['Squirtle', False, 1], ['Articuno', True, 1], ...]

Usa conversiones holísticas

names = ['Pikachu', 'Squirtle', 'Articuno', ...]
legend_status = [False, False, True, ...]
generations = [1, 1, 1, ...]

poke_data_tuples = []
for poke_tuple in zip(names, legend_status, generations):
    poke_data_tuples.append(poke_tuple)

poke_data = [*map(list, poke_data_tuples)]

print(poke_data)

[['Pikachu', False, 1], ['Squirtle', False, 1], ['Articuno', True, 1], ...]

%%timeit
poke_data = []
for poke_tuple in zip(names, legend_status, generations):
    poke_list = list(poke_tuple)
    poke_data.append(poke_list)

261 µs ± 23.2 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

%%timeit
poke_data_tuples = []
for poke_tuple in zip(names, legend_status, generations):
    poke_data_tuples.append(poke_tuple)

poke_data = [*map(list, poke_data_tuples)]

224 µs ± 1.67 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

¡Vamos a practicar!

Cómo escribir código Python eficiente