script to calculate travel times for long distances in D&D 5e

travel.py

import sys


SPEED_PER_HOUR = {
    'fast':   4,  # miles
    'normal': 3,
    'slow':   2,
}

TRAVEL_TIME_PER_DAY = {
    'fast':   7,  # hours
    'normal': 8,
    'slow':   9,
}


def calc_travel_time(distance, pace='normal', mounted=False):
    """ return number of days it will take to arrive """
    travelled = TRAVEL_TIME_PER_DAY[pace] * SPEED_PER_HOUR[pace]
    if mounted: # mounted only gives an extra hour of speed
        travelled += SPEED_PER_HOUR[pace]
    return round(distance / travelled, 1)

if __name__ == '__main__':
    if len(sys.argv) < 2:
        print(f'usage: <distance in miles> [--mounted]')
        exit(1)
    distance = int(sys.argv[1])
    mounted = '--mounted' in sys.argv

    for pace in ('fast', 'normal', 'slow'):
        travel_time = calc_travel_time(distance, pace, mounted)
        while_mounted = 'while mounted' if mounted else ''
        print(f'[{pace}]: \t {travel_time} days {while_mounted}')