Python -如果json数组中不存在键，则跳过键

Question

我有一个很大的json数组，它列出了某些键值对。数组中的每个元素应如下所示：

{
   "id" : "tmp3269879718695646867",
   "owner" : "johndoe",
   "x11-display" : ":7",
   "x11-authority" : "/run/user/1676/dcv/tmp3269879718695646867.xauth",
   "num-of-connections" : 0,
   "creation-time" : "2019-05-15T20:05:46.170274Z",
   "last-disconnection-time" : "2019-07-19T15:14:37.349168Z"
 },

然后，我在末尾附加一个开始方括号和一个结束方括号，以使其有效JSON。有时，数组中大约有100个元素。由于软件升级，如果用户未断开连接，则上次断开时间键不会出现在此输出上。我想做的是循环遍历数组中的每个元素，但如果上次断开连接时键不存在，则跳过整个元素。这是我到目前为止在循环中得到的：

for item in json_array:
        session_details = {"owner":None, "num-of-connections":None, "last-disconnection-time":None}
        session_details['owner'] = item['owner']
        user = item['owner']
        session_details['num-of-connections'] = item['num-of-connections']
        session_details['last-disconnection-time'] = item['last-disconnection-time']
        # Format date
        ...

我想要做的是在每次循环时检查项目。如下所示：

for item in json_array:
        session_details = {"owner":None, "num-of-connections":None, "last-disconnection-time":None}
        session_details['owner'] = item['owner']
        user = item['owner']
        session_details['num-of-connections'] = item['num-of-connections']
        if "last-disconnection-time" in json_array:
                session_details['last-disconnection-time'] = item['last-disconnection-time']
        else:
                print("last-disconnection-time does not exist in this array item")
        # Format date
        ...

但是，在运行脚本时，我仍然会得到KeyError。

Answer 1

您需要检查"last-disconnection-time“是否在项中。json_array是你的全部列表。item是一个字典，您想要在其中查找键是否存在。

if "last-disconnection-time" in item: