如何用Python从数千条此类记录中提取食物名称及营养成分名称和数值？

针对你手头数千条示例格式的JSON记录，以下是直接可复用的提取方案：

1. 先确保JSON格式合法 #

示例中的原始JSON存在格式缺失（最后一个dishes项未闭合），处理前要修复这类语法问题，否则解析会失败。

2. 基础提取代码 #

用Python内置的json模块解析数据，然后嵌套遍历提取目标字段：

import json

# 示例修复后的JSON字符串
raw_json = '[{"meal": "MY food", "dishes": [{"nutritions": [{"name": "Calories", "value": "412"}, {"name": "Carbs", "value": "29"}, {"name": "Fat", "value": "24"}, {"name": "Protein", "value": "21"}, {"name": "Sodium", "value": "258"}, {"name": "Sugar", "value": "29"}], "name": "my - McDonalds Espresso Pronto® Flat White, 2 TALL"}, {"nutritions": [{"name": "Calories", "value": "170"}, {"name": "Carbs", "value": "25"}, {"name": "Fat", "value": "5"}, {"name": "Protein", "value": "20"}, {"name": "Sodium", "value": "260"}, {"name": "Sugar", "value": "2"}], "name": "Quest Bar - Banana Nut Muffin Natural Protein Bar, 60 g"}, {"nutritions": [{"name": "Calories", "value": "176"}, {"name": "Carbs", "value": "33"}, {"name": "Fat", "value": "1"}, {"name": "Protein", "value": "5"}, {"name": "Sodium", "value": "195"}, {"name": "Sugar", "value": "0"}]}]}]'

# 解析JSON
data = json.loads(raw_json)

# 提取核心数据
extracted = []
for meal in data:
    for dish in meal["dishes"]:
        food_name = dish["name"]
        for nutrient in dish["nutritions"]:
            extracted.append({
                "食物名称": food_name,
                "营养成分": nutrient["name"],
                "数值": nutrient["value"]
            })

# 验证结果
for item in extracted[:3]:
    print(item)

3. 批量处理文件中的数千条记录 #

如果数据存储在JSON文件中（比如一个大数组或每行一条JSON），可以直接读取文件处理，还能把结果导出为CSV方便后续分析：

import json
import csv

# 读取批量JSON文件
with open("food_records.json", "r", encoding="utf-8") as f:
    data = json.load(f)

# 提取逻辑同上
extracted = []
for meal in data:
    for dish in meal["dishes"]:
        food_name = dish["name"]
        for nutrient in dish["nutritions"]:
            # 可选：将数值转为数字类型（处理非数值时加try-except）
            try:
                value = float(nutrient["value"])
            except ValueError:
                value = nutrient["value"]
            extracted.append({
                "食物名称": food_name,
                "营养成分": nutrient["name"],
                "数值": value
            })

# 导出为CSV
with open("nutrition_data.csv", "w", newline="", encoding="utf-8") as f:
    writer = csv.DictWriter(f, fieldnames=["食物名称", "营养成分", "数值"])
    writer.writeheader()
    writer.writerows(extracted)

注意事项 #

• 若原始JSON存在格式错误，可先用在线JSON校验工具排查，或在代码中加入try-except捕获异常并记录问题数据
• 针对超大规模数据，改用生成器（yield）逐步处理，避免内存溢出
• 数值转换时要考虑异常情况（比如非数字字符串），避免程序崩溃

内容的提问来源于stack exchange，提问作者Ahtisham Ali