如何使用Python对JSON值执行操作？

Question

我正在解析一个JSON文件。作为我对文件执行的操作的一部分，我需要从键"homeAbbr"中值为"ORE"的任何元素的100中减去yardLine键。不管代码是更新原始的yardLine键的值还是用修改后的值创建一个新的yardLineReal键—我两种方法都试过了，但新键更容易创建，这样就不会无限循环，这似乎是合乎逻辑的。下面是JSON的两个元素的示例-每个元素都有相同的键：

{
        "gameId": "400935253",
        "year": 2017,
        "week": 1,
        "homeId": "2483",
        "homeTeam": "Oregon",
        "homeAbbr": "ORE",
        "awayId": "253",
        "awayTeam": "Southern Utah",
        "awayAbbr": "SUU",
        "driveIndex": "2",
        "playIndex": "1",
        "offenseId": "2483",
        "offenseTeam": "Oregon",
        "offenseAbbr": "ORE",
        "defenseId": "253",
        "defenseTeam": "Southern Utah",
        "defenseAbbr": "SUU",
        "homeScore": 7,
        "awayScore": 7,
        "isScore": false,
        "quarter": 1,
        "clock": "11:39",
        "type": "Rush",
        "down": 1,
        "distance": 10,
        "yardLine": 26,
        "yardsGained": 14,
        "endYardLine": 40,
        "description": "Royce Freeman run for 14 yds to the Oregn 40 for a 1ST down"
    },
    {
        "gameId": "400935253",
        "year": 2017,
        "week": 1,
        "homeId": "2483",
        "homeTeam": "Oregon",
        "homeAbbr": "ORE",
        "awayId": "253",
        "awayTeam": "Southern Utah",
        "awayAbbr": "SUU",
        "driveIndex": "2",
        "playIndex": "2",
        "offenseId": "2483",
        "offenseTeam": "Oregon",
        "offenseAbbr": "ORE",
        "defenseId": "253",
        "defenseTeam": "Southern Utah",
        "defenseAbbr": "SUU",
        "homeScore": 7,
        "awayScore": 7,
        "isScore": false,
        "quarter": 1,
        "clock": "11:39",
        "type": "Rush",
        "down": 1,
        "distance": 10,
        "yardLine": 40,
        "yardsGained": 3,
        "endYardLine": 43,
        "description": "Royce Freeman run for 3 yds to the Oregn 43"
    }

下面是我提出的非函数代码，试图用编辑后的值创建一个名为yardLineReal的新键（我直接在yardLine中编辑值的非函数代码只在第8行中的键的名称不同）：

import json

with open ('data.json', 'r') as data_file:
    data = json.load(data_file)

for element in data:
    if 'ORE' in element["homeAbbr"]:
        data[yardLineReal] = 100 - data[yardLine]

with open('data.json', 'w') as data_file:
    data = json.dump(data, data_file)

我不相信代码会像编写的那样调用与yardLine关联的值。我想问题归根结底是，有没有办法引用这个值？你知道吗

谢谢：）

Answer 1

你可以只更新element本身。这将导致data也被更新：

import json

with open('data.json', 'r') as data_file:
    data = json.load(data_file)

for element in data:
    if 'ORE' in element['homeAbbr']:
        element['yardLineReal'] = 100 - element['yardLine']

with open('data.json', 'w') as data_file:
    data = json.dump(data, data_file, indent=4)

Answer 2

当然，您可以调用与“yardLine”相关联的值

这个代码是工作！你知道吗

for k, element in enumerate(data):
    if 'ORE' in element['homeAbbr']:
        data[k]['yardLine'] = 100 - element['yardLine']

结果：

{'awayAbbr': 'SUU',
  'awayId': '253',
  'awayScore': 7,
  'awayTeam': 'Southern Utah',
  'clock': '11:39',
  'defenseAbbr': 'SUU',
  'defenseId': '253',
  'defenseTeam': 'Southern Utah',
  'description': 'Royce Freeman run for 3 yds to the Oregn 43',
  'distance': 10,
  'down': 1,
  'driveIndex': '2',
  'endYardLine': 43,
  'gameId': '400935253',
  'homeAbbr': 'ORE',
  'homeId': '2483',
  'homeScore': 7,
  'homeTeam': 'Oregon',
  'isScore': False,
  'offenseAbbr': 'ORE',
  'offenseId': '2483',
  'offenseTeam': 'Oregon',
  'playIndex': '2',
  'quarter': 1,
  'type': 'Rush',
  'week': 1,
  'yardLine': 60, # before 40
  'yardsGained': 3,
  'year': 2017}

Answer 3

一旦将JSON文件加载到Python中，它就变成了一个字典。你可以这样迭代：

for key, value in data.items():
    if value == something:
        new_value = do_something(value)
        data[key] = new_value

我不确定你到底想做什么，但这应该能帮助你开始。你知道吗