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Mjukvaruutvecklingsprinciper i Python

Adam Spannbauer

Machine Learning Engineer

The Zen of Python

import this

The Zen of Python, by Tim Peters (abridged)

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
The complex is better than complicated.
Readability counts.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.

Beskrivande namngivning

Dålig namngivning

def check(x, y=100):
    return x >= y

Beskrivande namngivning

def is_boiling(temp, boiling_point=100):
    return temp >= boiling_point

Överdrivet

def check_if_temperature_is_above_boiling_point(
        temperature_to_check, 
        celsius_water_boiling_point=100):
    return temperature_to_check >= celsius_water_boiling_point

Håll det enkelt

The Zen of Python, by Tim Peters (abridged)

Simple is better than complex.
Complex is better than complicated.

Pizzabit

Att göra pizza – komplext

def make_pizza(ingredients):
    # Make dough
    dough = mix(ingredients['yeast'],
                ingredients['flour'],
                ingredients['water'],
                ingredients['salt'],
                ingredients['shortening'])

    kneaded_dough = knead(dough)
    risen_dough = prove(kneaded_dough)

    # Make sauce
    sauce_base = sautee(ingredients['onion'],
                                ingredients['garlic'],
                                ingredients['olive oil'])

    sauce_mixture = combine(sauce_base,
                            ingredients['tomato_paste'],
                            ingredients['water'],
                            ingredients['spices'])

    sauce = simmer(sauce_mixture)
    ...

Att göra pizza – enkelt

def make_pizza(ingredients):
    dough = make_dough(ingredients)
    sauce = make_sauce(ingredients)
    assembled_pizza = assemble_pizza(dough, sauce, ingredients)

    return bake(assembled_pizza)

När ska du refaktorera?

Dålig namngivning

def check(x, y=100):
    return x >= y

Beskrivande namngivning

def is_boiling(temp, boiling_point=100):
    return temp >= boiling_point

Överdrivet

def check_if_temperature_is_above_boiling_point(
        temperature_to_check, 
        celsius_water_boiling_point=100):
    return temperature_to_check >= celsius_water_boiling_point

Nu kör vi en övning!

Mjukvaruutvecklingsprinciper i Python