[英]How do I dig out field data in the XML file using Python and ElementTree
我正在嘗試使用Python和ElementTree模塊從Weathergoose設備讀取XML數據。 我可以從“設備”節點獲取“名稱”數據,但我想讀取“設備”節點下列出的數據。 我特別希望具有“ TempF”的值
這是XML數據的示例:
<server host="WeatherGoose" address="10.0.0.11" <omited stuff> tempunit="F">
<devices>
<device id="0114BE53110000E6" name="WeatherGoose" type="WxGoos" available="1" index="0">
<field key="TempC" value="20.55" niceName="Temperature (C)" min="-20" max="50" type="2"/>
<field key="TempF" value="68.99" niceName="Temperature (F)" min="-4" max="122" type="2"/>
<field key="Humidity" value="42.00" niceName="Relative Humidity" min="0" max="99" type="2"/>
<field key="Airflow" value="33.27" niceName="Air Flow" min="0" max="100" type="2"/>
<field key="Light" value="2.00" niceName="Light Level" min="1" max="99" type="2"/>
<field key="Sound" value="30.00" niceName="Sound Level" min="0" max="99" type="2"/>
<field key="IO1" value="99.00" niceName="Moisture" min="0" max="99" type="2"/>
<field key="IO2" value="99.00" niceName="IO-2" min="0" max="99" type="2"/>
<field key="IO3" value="0.00" niceName="Door Contacts" min="0" max="99" type="2"/>
</device>
</devices>
</server>
這是我到目前為止的內容:
import os
import urllib
import xml.etree.ElementTree as ET
def main():
feed = urllib.urlopen("http://10.0.0.11/data.xml")
try:
tree = ET.parse(feed)
root = tree.getroot()
event = root.find("devices")
for e in event:
print e.attrib['name']
except Exception, inst:
print "Error: %s: %s" % (tree, inst)
if __name__ == "__main__":
main()
這產生了設備的主機名,但是我找不到找到“現場密鑰”數據的魔力。 任何幫助,將不勝感激。
您應該能夠通過使用xpath field[@key='TempF']
(當前元素上下文為device
)來選擇具有值為TempF
的key
屬性的field
元素。
示例(將feed
更改回您的urllib調用)...
def main():
feed = "test.xml" # Used an external file for testing.
try:
tree = ET.parse(feed)
root = tree.getroot()
devices = root.findall("devices/device")
for device in devices:
print device.get("name")
print device.find("field[@key='TempF']").get("value")
except Exception, inst:
print "Error: %s" % inst
這將打印:
WeatherGoose
68.99
注意:如果您有多個device
元素,則會在每個元素上進行迭代。
下面的代碼遍歷xml並填充一個dict,其中鍵是設備ID,值是字典列表。 每個字典代表一個“字段”屬性。 僅收集定義為“有趣”的字段。
import xml.etree.ElementTree as ET
import pprint
xml = '''<server host="WeatherGoose" address="10.0.0.11" tempunit="F">
<devices>
<device id="0114BE53110000E6" name="WeatherGoose" type="WxGoos" available="1" index="0">
<field key="TempC" value="20.55" niceName="Temperature (C)" min="-20" max="50" type="2"/>
<field key="TempF" value="68.99" niceName="Temperature (F)" min="-4" max="122" type="2"/>
<field key="Humidity" value="42.00" niceName="Relative Humidity" min="0" max="99" type="2"/>
<field key="Airflow" value="33.27" niceName="Air Flow" min="0" max="100" type="2"/>
<field key="Light" value="2.00" niceName="Light Level" min="1" max="99" type="2"/>
<field key="Sound" value="30.00" niceName="Sound Level" min="0" max="99" type="2"/>
<field key="IO1" value="99.00" niceName="Moisture" min="0" max="99" type="2"/>
<field key="IO2" value="99.00" niceName="IO-2" min="0" max="99" type="2"/>
<field key="IO3" value="0.00" niceName="Door Contacts" min="0" max="99" type="2"/>
</device>
</devices>
</server>
'''
root = ET.fromstring(xml)
result = {}
interesting_fields = ['Airflow','TempF']
devices = root.findall('.//devices/device')
for device in devices:
result[device.attrib['id']] = [f.attrib for f in device.findall('./field') if f.attrib['key'] in interesting_fields]
pprint.pprint(result)
輸出
{'0114BE53110000E6': [{'key': 'TempF',
'max': '122',
'min': '-4',
'niceName': 'Temperature (F)',
'type': '2',
'value': '68.99'},
{'key': 'Airflow',
'max': '100',
'min': '0',
'niceName': 'Air Flow',
'type': '2',
'value': '33.27'}]}
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