Python - 用户生成的字典名称和输入

Question

This is my first SO question.

I am teaching myself to code using Python (and subsequently django). I am working on developing a website that allows local sailing regattas to create groups and track their results. Although this will eventually be a django project using a database, I wanted to write a simple script to 'sketch' the logic.

Objective : I would like a user to be able to create a Race Group, add boats to this group, and print various items.

Current Code : I have written the basic script that allows users to add boats to an existing race group:

#basic program logic to add boats to an existing race group;

#existing race group:

shediac = {
    'location':'Shediac NB',
    'year':2020,
    'boats': boats
}

#default boat list to pass into the race group

 boats=[
    {'name':'name1','owner':'owner1','handicap':0.00},  
]

#loop to take user input when adding new entries

answer=input('do you want to add a boat?: Y/N').upper()

while answer == 'Y':

    name = input('enter the boat name: ')
    owner = input('enter the boat owner''s name: ')
    handicap = input('enter the boat handicap: ')

    boats.append({
        'name': name,
        'handicap': handicap,
        'owner': owner,
        })

    # get user input again to retest for the while loop
    answer=input('do you want to add a boat?: Y/N').upper()

#prompt user to select information to display:

while true: 

what = input('what do you want to view: NAMES / OWNERS / HANDICAP / EXIT: 
').lower()

    if what == 'names':
        for boat in shediac['boats']:
            print(boat['name'])
    elif what == 'owners':
        for boat in shediac['boats']:
            print(boat['owner'])
    elif what == 'handicap':
        for boat in shediac['boats']:
            print(boat['handicap'])
    else:
        print('see you next time')

Challenge :

1. How do I get a user to create a new race group

2. How do I take the user input to generate the name of the new race group

I am using a dictionary for each race group, and passing in a list of boats (dictionaries containing various key value pairs). The existing code works to add boat entries to the existing race group (dictionary).

If my approach is entirely wrong, I welcome any better solutions! My primary interest is understanding how to approach such a problem.

Thanks.

Answer 1

While storing things inside dictionaries is fine, it's sometimes clearer to have dedicated types:

from dataclasses import dataclass
from typing import List

@dataclass
class Boat:
    name: str
    owner: str
    handicap: float

@dataclass
class RaceGroup:
    location: str
    year: int
    boats: List[Boat]

Next up, define a some input methods. Here's a method that returns a Boat :

def input_boat() -> Boat:
    name = input("enter the boat name: ")
    owner = input("enter the boat owner's name: ")
    handicap = float(input("enter the boat handicap: "))
    return Boat(name, owner, handicap)

Now for a method that returns a list of Boat s. We can reuse input_boat here inside a loop:

def input_boat_list() -> List[Boat]:
    boats = []
    while True:
        response = input('do you want to add a boat? [Y/N]: ').upper()
        if response == "N":
            return boats
        if response == "Y":
            boat = input_boat()
            boats.append(boat)

Here's a method that returns a RaceGroup :

def input_race_group() -> RaceGroup:
    location = input("enter the location: ")
    year = input("enter the year: ")
    boats = input_boat_list()
    return RaceGroup(location, year, boats)

Programming is easier and code becomes clearer when you break things up into subproblems!

---

We can now use the "library" of functions that we've created above in our main program:

default_boat_list = [
    Boat(name="name1", owner="owner1", handicap=0.00),  
]

shediac = RaceGroup(
    location="Shediac NB",
    year=2020,
    boats=list(default_boat_list),
    # list(...) creates a "shallow" copy of our earlier list
}

race_groups = [shediac]

while True:
    response = input('do you want to add a race group? [Y/N]: ').upper()
    if response == "N":
        break
    if response == "Y":
        race_group = input_race_group()
        race_group.boats = default_boat_list + race_group.boats
        race_groups.append(race_group)

print(race_groups)