Question

我正在尝试使用以下方法从Json文件中读取属性： d['text']['entities']['mention'][0]['screen_name']

Json文件

{
    "text" : {
        "content" : "@narendramodi Did u even know the fare of metro has been increased by 65%",

        "entities" : {
            "user_mentions" : [ ],
            "mention" : [
                {
                    "indices" : [
                        0,
                        13
                    ],
                    "id_str" : "18839785",
                    "screen_name" : "narendramodi",
                    "name" : "Narendra Modi",
                    "id" : 18839785
                }
            ],
            "hashtags" : [ ],
        },

    }
}

我正在尝试使用py2neo库在Neo4J数据库中加载许多json文件。

访问d['text']['entities']['mention'][0]['screen_name']时在其中"mention" : [ ],提及字段为空的json文件之一中，它表示

IndexError：列表索引超出范围

错误非常明显，但我该如何处理呢？

Answer 1

你可以使用try/except阻止。像

try:
  data = d['text']['entities']['mention'][0]['screen_name']
  ...
except IndexError:
  data = None # or handle this case in other way

Answer 2

试试这个 -

   mentions = d.get('text',{}).get('entities',{}).get('mention' ,[])
   if len(mentions)>0:
        print(mentions[0].get('screen_name',None))
   else:
        print(None)

从Json文件中读取值

2 个答案: