如何将文本文件转换为嵌套字典

Question

我是 Python 的初学者。我需要一些帮助将文本文件转换为嵌套的字典。具有一定的格式。

文本文件如下所示：

espresso, ingredients, water, 50, coffee, 18, cost, 1.5
latte, ingredients, water, 200, milk, 150, coffee, 24, cost, 2.5
cappuccino, ingredients, water, 250, milk, 100, coffee, 4, cost, 3.0

我试图让输出看起来像这样：

MENU = {"espresso": {"ingredients": {"water": 50, "coffee": 18}, "cost": 1.5},
        "latte": {"ingredients": {"water": 200, "milk": 150, "coffee": 24}, "cost": 2.5},
        "cappuccino": {"ingredients": {"water": 250, "milk": 100, "coffee": 24}, "cost": 3.0}}

这是我目前的代码：

def open_file() -> IO:
    """
    Ask the user for the input menu file and open it
    """

    file_pointer = None
    # prompts the user to enter a file name until a valid file is entered
    while file_pointer is None:
        # prompts the user to enter a file name
        file_name = input("Please enter a menu file: ")
        # try to open the file
        try:
            file_pointer = open(file_name, "r")
            # display an error message if cannot open file
        except IOError:
            print("An error has occurred, please try again. ")
    return file_pointer


def create_menu(fp: IO) -> Dict [str, Dict [str, float]]:
    """
    Creates a menu based on the inputted file in the form of a nested Dict
    """
    MENU = {}

    for line in fp:
        drink_detail = line.strip().split()

提前致谢！

Answer 1

以下代码将帮助您生成嵌套字典。您可以根据您的规格更改代码。

menu = {}

items = line.split(',')

drink = items[0]

ingredients = {}

for i in range(2, len(items)-2, 2):
    ingredient, amount = items[i], items[i+1]
    ingredients[ingredient.strip()] = float(amount.strip())

cost = float(items[-1].strip())

menu[drink] = {'ingredients': ingredients, 'cost': cost}

Answer 2

这并没有回答您关于返回嵌套字典的问题，但是根据您对数据的处理方式，将数据作为一系列数据类可能更容易。

此外，根据您对价值的处理方式，将钱存储为浮动可能会出现问题。更多详细信息，请访问： https://smirnov-am.github.io/representing-money-in-python/

从文件中提取数据到数据类的示例

import textwrap
from dataclasses import dataclass, field
from pathlib import Path
from typing import Optional


# Create menu file for testing
data_in = textwrap.dedent(
    """
    espresso, ingredients, water, 50, coffee, 18, cost, 1.5
    latte, ingredients, water, 200, milk, 150, coffee, 24, cost, 2.5
    cappuccino, ingredients, water, 250, milk, 100, coffee, 4, cost, 3.0
    """
)

file_name = "test_menu.txt"
Path(file_name).write_text(data_in, "utf8")
# End creating menu test file


@dataclass
class Ingredient:
    product: str
    qty: int


@dataclass
class Drink:
    name: str
    ingredients: list[Ingredient] = field(default_factory=list)
    cost: Optional[int] = None

    def show_ingredients(self) -> None:
        for ingredient in self.ingredients:
            print(f"\t{ingredient.product:<10}: {ingredient.qty:>4}")


@dataclass
class Menu:
    drinks: list[Drink] = field(default_factory=list)

    def get_drink(self, name: str) -> Drink:
        for drink in self.drinks:
            if drink.name.casefold() == name.casefold():
                return drink

    def add_drink(self, name: str) -> None:
        self.drinks.append(Drink(name))

    def add_cost(self, name: str, cost: int) -> None:
        drink = self.get_drink(name)
        drink.cost = cost

    def add_ingredient(self, drink_name: str, name: str, qty: int) -> None:
        drink = self.get_drink(drink_name)
        drink.ingredients.append(Ingredient(name, qty))

    def show_ingredients(self, drink_name: str) -> None:
        drink = self.get_drink(drink_name)
        print(f"Showing ingredients for {drink.name}")
        drink.show_ingredients()


def process_data(menu_data: str) -> Menu:
    menu = Menu()
    for drink in menu_data:
        drink_name = None
        for entry in drink:
            if entry[1] == "ingredients":
                drink_name = entry[0]
                menu.add_drink(drink_name)
            elif entry[0] == "cost":
                drink_price = int(float(entry[1]) * 100)
                menu.add_cost(drink_name, drink_price)
            else:
                menu.add_ingredient(drink_name, entry[0], int(entry[1]))
    return menu


def process_file(filepath: Path) -> Menu:
    menu_data = []
    for line in filepath.read_text('utf8').splitlines():
        if line:
            fields = line.split(",")
            menu_data.append(
                [(k.strip(), v.strip()) for k, v in zip(fields[::2], fields[1::2])]
            )
    return process_data(menu_data)


def main() -> None:

    menu = process_file(Path(file_name))
    for drink in menu.drinks:
        print(drink)

    print("\nShow just one drink:")
    menu.show_ingredients('latte')

    print("\nShow ingredients for all drinks:")
    for drink in menu.drinks:
        print(f"Showing ingredients for {drink.name}")
        drink.show_ingredients()


if __name__ == "__main__":
    main()

这个例子给了我以下输出：

Drink(name='espresso', ingredients=[Ingredient(product='water', qty=50), Ingredient(product='coffee', qty=18)], cost=150)
Drink(name='latte', ingredients=[Ingredient(product='water', qty=200), Ingredient(product='milk', qty=150), Ingredient(product='coffee', qty=24)], cost=250)
Drink(name='cappuccino', ingredients=[Ingredient(product='water', qty=250), Ingredient(product='milk', qty=100), Ingredient(product='coffee', qty=4)], cost=300)

Show just one drink:
Showing ingredients for latte
    water     :  200
    milk      :  150
    coffee    :   24

Show ingredients for all drinks:
Showing ingredients for espresso
    water     :   50
    coffee    :   18
Showing ingredients for latte
    water     :  200
    milk      :  150
    coffee    :   24
Showing ingredients for cappuccino
    water     :  250
    milk      :  100
    coffee    :    4

Answer 3

menu_dict = {}

with open("yourTextFile.txt", "r") as data:
    for row in data:
        temp_row = row.split(",")
        key = temp_row[0]
        if key not in menu_dict.keys():
            menu_dict[key] = {"ingredients": {}, "cost": temp_row[-1]}

        for i in range(2, len(temp_row) - 2, 2):
            menu_dict[key]["ingredients"][temp_row[i]] = temp_row[i + 1]

    print(menu_dict)