从网站解析Python XML

Question

我想从一个网站解析.我被卡住了.我将在下面提供XML.它来自一个网站.我有两个问题.从网站读取xml的最佳方法是什么,然后我无法深入挖掘xml以获得我需要的速率.

我需要的数字是Base:OBS_VALUE 0.12

到目前为止我所拥有的:

from xml.dom import minidom
import urllib


document = ('http://www.newyorkfed.org/markets/omo/dmm/fftoXML.cfm?type=daily''r')
web = urllib.urlopen(document)
get_web = web.read()
xmldoc = minidom.parseString(document)

ff_DataSet = xmldoc.getElementsByTagName('ff:DataSet')[0]

ff_series = ff_DataSet.getElementsByTagName('ff:Series')[0]

for line in ff_series:
    price = line.getElementsByTagName('base:OBS_VALUE')[0].firstChild.data
    print(price)

来自网站的XML代码:

-<Header> <ID>FFD</ID>
 <Test>false</Test> 
 <Name xml:lang="en">Federal Funds daily averages</Name> <Prepared>2013-05-08</Prepared>
 <Sender id="FRBNY"> <Name xml:lang="en">Federal Reserve Bank of New York</Name> 
<Contact>   
<Name xml:lang="en">Public Information Web Team</Name> <Email>ny.piwebteam@ny.frb.org</Email>  
</Contact> 
</Sender> 
<!--ReportingBegin></ReportingBegin-->
</Header> 
<ff:DataSet> -<ff:Series TIME_FORMAT="P1D" DISCLAIMER="G" FF_METHOD="D" DECIMALS="2" AVAILABILITY="A"> 
<ffbase:Key> 
<base:FREQ>D</base:FREQ> 
<base:RATE>FF</base:RATE>
<base:MATURITY>O</base:MATURITY> 
<ffbase:FF_SCOPE>D</ffbase:FF_SCOPE> 
</ffbase:Key> 
<ff:Obs OBS_CONF="F" OBS_STATUS="A">
<base:TIME_PERIOD>2013-05-07</base:TIME_PERIOD>
<base:OBS_VALUE>0.12</base:OBS_VALUE>

Answer 1

如果你想坚持使用xml.dom.minidom,试试这个......

from xml.dom import minidom
import urllib

url_str = 'http://www.newyorkfed.org/markets/omo/dmm/fftoXML.cfm?type=daily'
xml_str = urllib.urlopen(url_str).read()
xmldoc = minidom.parseString(xml_str)

obs_values = xmldoc.getElementsByTagName('base:OBS_VALUE')
# prints the first base:OBS_VALUE it finds
print obs_values[0].firstChild.nodeValue

# prints the second base:OBS_VALUE it finds
print obs_values[1].firstChild.nodeValue

# prints all base:OBS_VALUE in the XML document
for obs_val in obs_values:
    print obs_val.firstChild.nodeValue

但是,如果要使用lxml,请使用underrun的解决方案.此外,您的原始代码有一些错误.您实际上是在尝试解析文档变量,即Web地址.您需要解析从网站返回的xml,在您的示例中是get_web变量.