在解析此xml文件时产生此KeyError的原因是什么？

Question

我有一个我正在尝试解析的xml文件。这是一个样本

</Event>


-<Event timestamp="2016-08-14T14:23:33.634" id="1713385925" 
version="1471181110290" last_modified="2016-08-14T14:25:11" y="11.0" 
x="89.7" outcome="0" team_id="148" player_id="51327" sec="8" min="23" 
period_id="1" type_id="4" event_id="205">

<Q id="733814222" qualifier_id="265"/>

<Q id="481660420" qualifier_id="286"/>

<Q id="813378778" qualifier_id="152"/>

<Q id="570443899" qualifier_id="56" value="Right"/>

<Q id="420312891" qualifier_id="233" value="248"/>

<Q id="1186861264" qualifier_id="13"/>

</Event>


-<Event timestamp="2016-08-14T14:23:33.634" id="1635888622" 
version="1471181110289" last_modified="2016-08-14T14:25:11" y="89.0" 
x="10.3" outcome="1" team_id="143" player_id="169007" sec="8" min="23" 
period_id="1" type_id="4" event_id="248">

<Q id="1871787686" qualifier_id="56" value="Back"/>

<Q id="176295814" qualifier_id="13"/>

<Q id="69346842" qualifier_id="233" value="205"/>

<Q id="1588029344" qualifier_id="265"/>

<Q id="559785299" qualifier_id="285"/>

<Q id="380723313" qualifier_id="152"/>

它充满了这样的事件。我可以访问所有其他属性（outcome，type_id等）和子标签，但不能为player_id的属性值执行此操作。错误是 - 这里是我用来解析它的xmldom代码的示例。

xml = xmldoc.getElementsByTagName("Games")[0]
Events = xml.getElementsByTagName("Event")

for event in Events:
    typeid = event.attributes["type_id"]
    typeidval = typeid.value

    player = event.attributes["player_id"]
    playeridval = player.value

    teamid = event.attributes["team_id"]
    teamidval = teamid.value

    outcomeid = event.attributes["outcome"]
    outcomeidval = outcomeid.value

有人可以帮我解决xmldom / minidom代码来解决这个问题吗？我究竟做错了什么？

Answer 1

一个丑陋的修复方法是处理player_id属性的异常，并在抛出异常时将值设置为""：

try:
    player = event.attributes["player_id"]
    playeridval = player.value
except:
    playeridval = ""

Answer 2

更清洁的方法：

player = event.attributes.get("player_id",None)
playeridval = player.value if player else ""