python etree.ElementTree는 다양한 네임 스페이스로 구문 분석

Question

정확하게는 online resource을 구문 분석해야하지만 .xml 파일을 currency.py 파일이있는 디렉토리로 복사하여 단순화하려고했습니다. 그렇다면 내 눈에있는 복잡한 일로 인해 매우 짧습니다 manual here로 시작했습니다. 이 샘플에서는 파일을 3 개의 항목과 2 개의 currencys로 잘라서 단순하게하기 위해 문자열로 구문 분석합니다.

import xml.etree.ElementTree as ET 
#tree = ET.ElementTree(file='currency.xml') 
data = ''' 
<rdf:RDF xmlns:cb="http://www.cbwiki.net/wiki/index.php/Specification_1.2/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://purl.org/rss/1.0/"> 
    <channel rdf:about="https://www.snb.ch/de/ifor/media/id/media_rss"> 
    <title>SNB Devisenkurse</title> 
    <link>https://www.snb.ch/de/ifor/media/id/media_rss</link> 
    <description>Schweizerische Nationalbank (SNB): Devisenkurse (Ankauf Zürich 11 Uhr)</description> 
    <items> 
     <rdf:Seq> 
     <rdf:li rdf:resource="https://www.snb.ch#GBP_4782176f7871403c002581de004629c7"/> 
     <rdf:li rdf:resource="https://www.snb.ch#JPY_4782176f7871403c002581de004629c7"/> 
     <rdf:li rdf:resource="https://www.snb.ch#EUR_4782176f7871403c002581de004629c7"/> 
     <!-- here are more currencys... --> 
     </rdf:Seq> 
    </items> 
    <dc:publisher>SNB</dc:publisher> 
    <dc:rights>Copyright © Schweizerische Nationalbank, Zürich (Schweiz) 2017</dc:rights> 
    <dcterms:license>https://www.snb.ch/de/srv/id/disclaimer</dcterms:license> 
    <dcterms:created>2017-11-20T19:30:01+01:00</dcterms:created> 
    </channel> 
    <item rdf:about="https://www.snb.ch#GBP_4782176f7871403c002581de004629c7"> 
    <title>CH: 1.3116 CHF = 1 GBP 2017-11-20 Tägliche Kurse (11:00)</title> 
    <link>https://www.snb.ch</link> 
    <description>1 GBP = 1.3116 CHF (Tägliche Kurse (11:00); 2017-11-20T13:46:22.357+01:00)</description> 
    <dc:date>2017-11-20T13:46:22.357+01:00</dc:date> 
    <dc:language>de</dc:language> 
    <cb:statistics rdf:parseType="Resource"> 
     <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#Statistics"/> 
     <cb:country>CH</cb:country> 
     <cb:institutionAbbrev>SNB</cb:institutionAbbrev> 
     <cb:exchangeRate rdf:parseType="Resource"> 
     <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#ExchangeRate"/> 
     <cb:observation rdf:parseType="Resource"> 
      <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#Observation"/> 
      <cb:value>1.3116</cb:value> 
      <cb:unit>CHF</cb:unit> 
      <cb:decimals>4</cb:decimals> 
     </cb:observation> 
     <cb:baseCurrency>CHF</cb:baseCurrency> 
     <cb:targetCurrency>GBP</cb:targetCurrency> 
     <cb:rateType>Tägliche Kurse (11:00)</cb:rateType> 
     <cb:observationPeriod rdf:parseType="Resource"> 
      <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#ObservationPeriod"/> 
      <cb:frequency>daily</cb:frequency> 
      <cb:period>2017-11-20</cb:period> 
     </cb:observationPeriod> 
     </cb:exchangeRate> 
    </cb:statistics> 
    </item> 
    <item rdf:about="https://www.snb.ch#JPY_4782176f7871403c002581de004629c7"> 
    <title>CH: 0.8819 CHF = 100 JPY 2017-11-20 Tägliche Kurse (11:00)</title> 
    <link>https://www.snb.ch</link> 
    <description>100 JPY = 0.8819 CHF (Tägliche Kurse (11:00); 2017-11-20T13:46:22.350+01:00)</description> 
    <dc:date>2017-11-20T13:46:22.350+01:00</dc:date> 
    <dc:language>de</dc:language> 
    <cb:statistics rdf:parseType="Resource"> 
     <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#Statistics"/> 
     <cb:country>CH</cb:country> 
     <cb:institutionAbbrev>SNB</cb:institutionAbbrev> 
     <cb:exchangeRate rdf:parseType="Resource"> 
     <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#ExchangeRate"/> 
     <cb:observation rdf:parseType="Resource"> 
      <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#Observation"/> 
      <cb:value>0.8819</cb:value> 
      <cb:unit>CHF</cb:unit> 
      <cb:unit_mult>-2</cb:unit_mult> 
      <cb:decimals>4</cb:decimals> 
     </cb:observation> 
     <cb:baseCurrency>CHF</cb:baseCurrency> 
     <cb:targetCurrency>JPY</cb:targetCurrency> 
     <cb:rateType>Tägliche Kurse (11:00)</cb:rateType> 
     <cb:observationPeriod rdf:parseType="Resource"> 
      <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#ObservationPeriod"/> 
      <cb:frequency>daily</cb:frequency> 
      <cb:period>2017-11-20</cb:period> 
     </cb:observationPeriod> 
     </cb:exchangeRate> 
    </cb:statistics> 
    </item> 
    <item rdf:about="https://www.snb.ch#EUR_4782176f7871403c002581de004629c7"> 
    <title>CH: 1.1665 CHF = 1 EUR 2017-11-20 Tägliche Kurse (11:00)</title> 
    <link>https://www.snb.ch</link> 
    <description>1 EUR = 1.1665 CHF (Tägliche Kurse (11:00); 2017-11-20T13:46:22.343+01:00)</description> 
    <dc:date>2017-11-20T13:46:22.343+01:00</dc:date> 
    <dc:language>de</dc:language> 
    <cb:statistics rdf:parseType="Resource"> 
     <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#Statistics"/> 
     <cb:country>CH</cb:country> 
     <cb:institutionAbbrev>SNB</cb:institutionAbbrev> 
     <cb:exchangeRate rdf:parseType="Resource"> 
     <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#ExchangeRate"/> 
     <cb:observation rdf:parseType="Resource"> 
      <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#Observation"/> 
      <cb:value>1.1665</cb:value> 
      <cb:unit>CHF</cb:unit> 
      <cb:decimals>4</cb:decimals> 
     </cb:observation> 
     <cb:baseCurrency>CHF</cb:baseCurrency> 
     <cb:targetCurrency>EUR</cb:targetCurrency> 
     <cb:rateType>Tägliche Kurse (11:00)</cb:rateType> 
     <cb:observationPeriod rdf:parseType="Resource"> 
      <rdf:type rdf:resource="http://www.cbwiki.net/wiki/index.php/RSS-CB_1.2_RDF_Schema#ObservationPeriod"/> 
      <cb:frequency>daily</cb:frequency> 
      <cb:period>2017-11-20</cb:period> 
     </cb:observationPeriod> 
     </cb:exchangeRate> 
    </cb:statistics> 
    </item> 
<!-- here are more currencys... --> 
</rdf:RDF>''' 
tree = ET.fromstring(data) 
ns = {'rdf':'http://www.w3.org/1999/02/22-rdf-syntax-ns#', 
    'cb': 'http://www.cbwiki.net/wiki/index.php/Specification_1.2/'} 
for item in tree.findall('item'): 
    for stat in item.findall('cb:statistics', ns): 
     for exrate in stat.findall('cb:exchangeRate', ns): 
      currency = exrate.find('cb:targetCurrency', ns).text 
      print(currency) 

이렇게 MWE가됩니다. 내가 뭘 actualy하는 일은 말에 단지 몇 줄 : 나는 고원

... python3의 currency.py 아무 일도 발생하지 통화를하고 싶으 :

tree = ET.fromstring(data) 
ns = {'rdf':'http://www.w3.org/1999/02/22-rdf-syntax-ns#', 
    'cb': 'http://www.cbwiki.net/wiki/index.php/Specification_1.2/'} 
for item in tree.findall('item'): 
    for stat in item.findall('cb:statistics', ns): 
     for exrate in stat.findall('cb:exchangeRate', ns): 
      currency = exrate.find('cb:targetCurrency', ns).text 
      print(currency) 

지금 단자와 executeing에가는 JPY (cb : targetCurrency)를 곱하여 10 x (cb : unit_mult) 필드와 곱하십시오. 하지만 지금까지 나는 노드의 텍스트를 얻을 수 없습니다 ... 어떻게하면 통화를 얻을 수 있습니까?

솔루션 :

import xml.etree.ElementTree as ET 
# terminal: cd to this .py file and then do 
# $wget https://www.snb.ch/selector/de/mmr/exfeed/rss 
# rename the file to rss.xml 
tree = ET.ElementTree(file='rss.xml') 
root = tree.getroot() 
ns = {'rdf':'http://www.w3.org/1999/02/22-rdf-syntax-ns#', 
    'none':'http://purl.org/rss/1.0/', 
    'dc':'http://purl.org/dc/elements/1.1/', 
    'dcterms':'http://purl.org/dc/terms/', 
    'cb': 'http://www.cbwiki.net/wiki/index.php/Specification_1.2/'} 

for item in root.findall('none:item',ns): 
    for statistics in item.findall('cb:statistics',ns): 
     for exchangerate in statistics.findall('cb:exchangeRate',ns): 
      for targetcurrency in exchangerate.findall('cb:targetCurrency',ns): 
       print(targetcurrency.text) 

Answer 1

당신은 기본 네임 스페이스을 고려하지 않았다. 접두사가없는 후손 요소는 암시 통해 반복하려고 item 요소를 포함이 네임 스페이스 즉 상속 :

ns = {'d': 'http://purl.org/rss/1.0/', 
    ....} 
for item in tree.findall('d:item', ns): 
    .....