如何循环/返回Python中的所有JSON响应

Question

前言:我花了一段时间做一个轻巧的桌面应用程序开发人员(VBA和SQL -请告我！)，但我对python完全陌生。

我试图在Python中打印JSON提要的输出，作为培训练习：

JSON http://www.nactem.ac.uk/software/acromine/dictionary.py?sf=uk

[
    {
        "lfs": [
            {
                "freq": 656,
                "lf": "United Kingdom",
                "since": 1980,
                "vars": [
                    {
                        "freq": 655,
                        "lf": "United Kingdom",
                        "since": 1980
                    },
                    {
                        "freq": 1,
                        "lf": "United-Kingdom",
                        "since": 2006
                    }
                ]
            },
            {
                "freq": 393,
                "lf": "urokinase",
                "since": 1969,
                "vars": [
                    {
                        "freq": 358,
                        "lf": "urokinase",
                        "since": 1969
                    },
                    {
                        "freq": 35,
                        "lf": "Urokinase",
                        "since": 1970
                    }
                ]
            },
            {
                "freq": 6,
                "lf": "uridine kinase",
                "since": 1977,
                "vars": [
                    {
                        "freq": 5,
                        "lf": "uridine kinase",
                        "since": 1977
                    },
                    {
                        "freq": 1,
                        "lf": "Uridine kinase",
                        "since": 2007
                    }
                ]
            },
            {
                "freq": 6,
                "lf": "urinary kallikrein",
                "since": 1985,
                "vars": [
                    {
                        "freq": 6,
                        "lf": "urinary kallikrein",
                        "since": 1985
                    }
                ]
            },
            {
                "freq": 4,
                "lf": "urea kinetics",
                "since": 1980,
                "vars": [
                    {
                        "freq": 2,
                        "lf": "urea kinetics",
                        "since": 1980
                    },
                    {
                        "freq": 2,
                        "lf": "urea kinetic",
                        "since": 1989
                    }
                ]
            },
            {
                "freq": 4,
                "lf": "University of Kentucky",
                "since": 2000,
                "vars": [
                    {
                        "freq": 4,
                        "lf": "University of Kentucky",
                        "since": 2000
                    }
                ]
            }
        ],
        "sf": "UK"
    }
]

到目前为止，我只知道如何使用以下代码一次返回一个结果：

import urllib.request
import json

def main():

  SearchForAbbrev = input("Please enter an abbreviation to search for:")
  urlData = "http://www.nactem.ac.uk/software/acromine/dictionary.py?sf=" + SearchForAbbrev

  webUrl = urllib.request.urlopen(urlData)
  print (webUrl.getcode())
  if (webUrl.getcode() == 200):
    data = webUrl.read()
    data = data.decode("utf-8") 
    printResults(data)

  else:
    print ("Received an error from server, cannot retrieve results " + str(webUrl.getcode()))


def printResults(data):

  theJSON = json.loads(data)

  for i in theJSON:

    print(i["lfs"][0]["lf"])

一开始，我试着在没有joy的情况下使用类似print(i["lfs"]["lf"])的东西。

TypeError:列表索引必须是整数或切片，而不是str

问题：如何循环遍历0(索引？)值，以返回所有结果。

对于奖金作为后续，我如何返回所有相关的结果在vars？

Answer 1

如果您仔细查看正在输出的JSON，您可以看到：

1. 一排排的骰子
2. 在每个dict中，lfs是一个包含多个dicts的数组。
3. 每个dicts内部都有一个名为vars的键，这是另一个dicts数组。
4. 正是在这段代码中，您尝试打印的lf才能被找到。

因此，您只是简单地不正确地访问JSON数据。您的打印功能应该如下：

def printResults(data):
    js = json.loads(data)
    for d in js:
        print(d["lfs"][0]["vars"][0]["lf"])

或者，如果你想打印所有的lf：

for d in js:
    for e in d["lfs"]:
        for f in e["vars"]:
            print(f["lf"])

Answer 2

最自然的，循环可以通过.组织一个循环：

  for i in theJSON:
    for j in i["lfs"]:
      print(j["lf"])

它也可以做一个一条龙：

print([j["lf"] for j in i["lfs"] for i in theJSON])

那是一条快乐的道路。检查无效输入并对vars执行此操作作为练习。