Python新手求助：如何将文本文件转换为指定格式的嵌套Dictionary

我是Python初学者，需要帮助将特定格式的文本文件转换为嵌套字典。

文本文件内容： #

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

期望输出： #

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": 4}, "cost": 3.0}}

已编写的代码： #

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()

补全后的完整代码： #

from typing import IO, Dict

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:
        # 按逗号分割文本，并去除每个元素的多余空格
        drink_detail = [item.strip() for item in line.strip().split(',')]
        # 提取饮品名称作为外层字典的键
        drink_name = drink_detail[0]
        # 初始化当前饮品的嵌套字典结构
        drink_dict = {"ingredients": {}}
        
        i = 1
        while i < len(drink_detail):
            current_key = drink_detail[i]
            if current_key == "ingredients":
                # 遍历处理食材组：每两个元素为一组（食材名+数量）
                i += 1
                while i < len(drink_detail) and drink_detail[i] != "cost":
                    ingredient = drink_detail[i]
                    amount = int(drink_detail[i+1])
                    drink_dict["ingredients"][ingredient] = amount
                    i += 2
            elif current_key == "cost":
                # 处理价格，转换为浮点数
                drink_dict["cost"] = float(drink_detail[i+1])
                i += 2
        
        # 将当前饮品字典加入总菜单
        MENU[drink_name] = drink_dict
    
    return MENU

# 测试执行
if __name__ == "__main__":
    file = open_file()
    menu_result = create_menu(file)
    file.close()
    print("MENU =", menu_result)

关键逻辑说明： #

• 文本分割修正：原文本用逗号分隔，所以改用逗号分割后再清理每个元素的空格，避免因空格导致的解析错误。
• 分层解析：先提取饮品名，再分别处理ingredients和cost模块，食材部分按"名称-数量"的成对规则解析，价格单独转换为浮点数。
• 类型转换：将食材数量转为整数、价格转为浮点数，匹配期望输出的类型要求。

内容的提问来源于stack exchange，提问作者lnhmai