introduction.md

Introduction

Yacht in Python can be solved in many ways. The most intuitive approach is to use an if structure. Alternatively, you can create functions and set their names to the constant names.

General guidance

The main thing in this exercise is to map a category (here defined as constants in the stub file) to a function or a standalone piece of code. While mapping generally reminds us of dictionaries, here the constants are global. This indicates that the most idiomatic approach is not using a dict. Adhering to the principles of DRY is important - don't repeat yourself if you can help it, especially in the ONES through SIXES categories!

Approach: functions

Each bit of functionality for each category can be encoded in a function, and the constant name set to that function. This can be done by assigning the constant name to a lambda or creating a one-line function using the constant as a function name.

def digits(num):
    return lambda dice: dice.count(num) * num
YACHT = lambda dice: 50 if dice.count(dice[0]) == len(dice) else 0
ONES = digits(1)
TWOS = digits(2)
THREES = digits(3)
FOURS = digits(4)
FIVES = digits(5)
SIXES = digits(6)
FULL_HOUSE = lambda dice: sum(dice) if len(set(dice)) == 2 and dice.count(dice[0]) in [2, 3] else 0
FOUR_OF_A_KIND = lambda dice: 4 * dice[1] if dice[0] == dice[3] or dice[1] == dice[4] else 0
LITTLE_STRAIGHT = lambda dice: 30 if sorted(dice) == [1, 2, 3, 4, 5] else 0
BIG_STRAIGHT = lambda dice: 30 if sorted(dice) == [2, 3, 4, 5, 6] else 0
CHOICE = sum
def score(dice, category):
    return category(dice)

This is a very succinct way to solve the exercise, although some one-liners get a little long. For more information on this approach, read this document.

Approach: if structure

The constants can be set to random, null, or numeric values, and an if structure inside score determines the code to be executed. As one-liners aren't necessary here, we can spread out the code to make it look neater:

ONES = 1
TWOS = 2
THREES = 3
FOURS = 4
FIVES = 5
SIXES = 6
FULL_HOUSE = 'FULL_HOUSE'
FOUR_OF_A_KIND = 'FOUR_OF_A_KIND'
LITTLE_STRAIGHT = 'LITTLE_STRAIGHT'
BIG_STRAIGHT = 'BIG_STRAIGHT'
CHOICE = 'CHOICE'
YACHT = 'YACHT'
def score(dice, category):
    if category in (1,2,3,4,5,6):
         return dice.count(category) * category
    elif category == 'FULL_HOUSE':
        if len(set(dice)) == 2 and dice.count(dice[0]) in [2, 3]:
            return sum(dice) or 0
    elif category == 'FOUR_OF_A_KIND':
        if dice[0] == dice[3] or dice[1] == dice[4]:
            return dice[1] * 4 or 0
    elif category == 'LITTLE_STRAIGHT':
        if sorted(dice) == [1, 2, 3, 4, 5]: 
            return 30 or 0
    elif category == 'BIG_STRAIGHT':
        if sorted(dice) == [2, 3, 4, 5, 6]:
            return 30 or 0
    elif category == 'YACHT':
        if all(num == dice[0] for num in dice):
            return 50
    elif category == 'CHOICE':
        return sum(dice)
    return 0

Read more on this approach here.