使用Python在JSON中查找值 [英] Find a value in JSON using Python

问题描述

我以前曾经成功地从JSON文件中解析数据，但是现在我要实现的功能遇到了问题.我在JSON中有一个名称，标识号和生日的列表.我想要在Python中获得的功能是能够让用户输入名称并检索其标识号和生日(如果存在).

I’ve previously succeeded in parsing data from a JSON file, but now I’m facing a problem with the function I want to achieve. I have a list of names, identification numbers and birthdate in a JSON. What I want to get in Python is to be able to let a user input a name and retrieve his identification number and the birthdate (if present).

这是我的JSON示例文件:

This is my JSON example file:

[
 {
   "id_number": "SA4784",
   "name": "Mark",
   "birthdate": null
 },
 {
   "id_number": "V410Z8",
   "name": "Vincent",
   "birthdate": "15/02/1989"
 },
 {
   "id_number": "CZ1094",
   "name": "Paul",
   "birthdate": "27/09/1994"
 }
]

要清楚，我想输入"V410Z8"并获取他的名字和生日.

To be clear, I want to input "V410Z8" and get his name and his birthdate.

我试图用Python编写一些代码，但是我只成功搜索了"id_number"，而不是"id_number"内部的内容，例如"V410Z8".

I tried to write some code in Python but I only succeed in searching for "id_number" and not for what is inside "id_number" for example "V410Z8".

#!/usr/bin/python
# -*- coding: utf-8 -*-

import json 

database = "example.json"
data = json.loads(open(database).read())

id_number = data[0]["id_number"]
print id_number

谢谢你们的支持，伙计们:)

Thank you for your support, guys :)

推荐答案

您必须遍历字典列表，并使用给定的id_number搜索字典.一旦找到它，就可以打印其其余数据并中断，前提是id_number是唯一的.

You have to iterate over the list of dictionaries and search for the one with the given id_number. Once you find it you can print the rest of its data and break, assuming id_number is unique.

data = [
 {
   "id_number": "SA4784",
   "name": "Mark",
   "birthdate": None
 },
 {
   "id_number": "V410Z8",
   "name": "Vincent",
   "birthdate": "15/02/1989"
 },
 {
   "id_number": "CZ1094",
   "name": "Paul",
   "birthdate": "27/09/1994"
 }
]

for i in data:
    if i['id_number'] == 'V410Z8':
        print(i['birthdate'])
        print(i['name'])
        break

如果您可以控制数据结构，则更有效的方法是使用id_number作为键(同样，假设id_number是唯一的):

If you have control over the data structure, a more efficient way would be to use the id_number as a key (again, assuming id_number is unique):

data =  { "SA4784" : {"name": "Mark", "birthdate": None},
          "V410Z8" : { "name": "Vincent", "birthdate": "15/02/1989"},
          "CZ1094" : {"name": "Paul", "birthdate": "27/09/1994"}
        }

然后您需要做的就是尝试直接访问它:

Then all you need to do is try to access it directly:

try:
    print(data["V410Z8"]["name"])
except KeyError:
    print("ID doesn't exist")
>> "Vincent"

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