如何使用R

时间:2017-01-11 13:06:50

标签: r xml web-scraping html-parsing

link for the xml text. please remove "http:" from the link text

下面的

是xml文本内容。

<?xml version="1.0" standalone="yes"?>
  <hydstra_xml_store date_format="BRITISH" version="1" application="WEBBATLS" timestamp="20170111144727">
   <webbatls>
   <site station="G0010001" parent="" stname="Sandover River - #7 Bore" shortname="Sandover R #7 Bore" mapname="" zone="53" easting="476064.2" northing="7552556.9" grdatum="MGA94" latitude="-22.131884543" longitude="134.767896023" lldatum="GDA94" posacc="" elev="12.658" elevdatum="" elevacc="01" local_map="" timezone="9.5" qquarter="" quarter="" section="" township="" range="" meridian="" active="False" owner="" commence="16/10/1968" cease="15/05/1974" stntype="SWG" region="5" orgcode="NTP" barcode="" category1="" category2="" category3="" category4="" category5="" category6="" category7="" category8="" category9="" category10="" category11="" category12="" category13="" category14="" category15="" category16="" category17="" category18="" category19="" category20="" spare1="" spare2="" enteredby="" checkedby="HYD" comment="" dbver41="" datecreate="30/12/1899" timecreate="0" usercreate="" datemod="09/12/2016" timemod="1111" usermod="BAILJ">
   <_decode_ station="Sandover R #7 Bore" parent="(None)" grdatum="Map Grid of Australia 1994" latitude="22&#176;07&apos;54.8&quot;S" longitude="134&#176;46&apos;04.4&quot;E" lldatum="Geodetic Datum of Australia 1994" posacc="Prec unknown" elevdatum="(unknown)" elevacc="Not Applicable" timezone="Offset of standard local time from GMT" meridian="Unspecified" owner="(None)" stntype="SW Gauging Station" region="NT Wide" orgcode="NT Water Resources" category1="(Not set)" category2="(Not set)" category3="(Not set)" category4="(unknown)" category5="Unknown" category6="Unknown" category7="Unknown" category8="Unknown" category9="Unknown" category10="Unknown" category11="(unknown)" category12="(unknown)" category13="(unknown)" category14="(unknown)" category15="(unknown)" category16="(unknown)" category17="(unknown)" category18="(unknown)" category19="(unknown)" category20="(unknown)" enteredby="(unknown)" checkedby="HYDMG &lt;Data imported by H"/>
</site>
<station station="G0010001" gauge="0" datum="GD" control="sandy river bed" contcode="" ctf="1.368" downst="False" gaugfacil="" hut="False" telemetry="False" streamdist="0" phone="" spillway="0" qmin="0" tmin="0" maxgaug="0" maxgdate="30/12/1899" catcharea="5050" enteredby="DRK" checkedby="HYD" bedslope="0" order="0" spare1="" spare2="" spare3="" spare4="" spare5="" dbver22="" datecreate="30/12/1899" timecreate="0" usercreate="" datemod="03/01/2017" timemod="212" usermod="SVCACC">
<_decode_ station="Sandover R #7 Bore" datum="Gauge Datum" contcode="Unknown" streamdist="km" tmin="Mins" catcharea="sq. km" enteredby="Doug Kinter" checkedby="HYDMG &lt;Data imported by H" spare1="(unknown)" spare2="(unknown)" spare3="(unknown)" spare4="(unknown)" spare5="(unknown)"/>
</station>
<stninis/>
<periods/>
<gwholes/>
<aquifers/>
<variables/>
<contents_lists>
<content_list secttype="Reports" secttypestr="Reports" section="WEBREPORTSDWHSW"/>
<content_list secttype="Documents" secttypestr="Documents" section="WEBDOCUMENTSDWHSW"/>
</contents_lists>
</webbatls>
</hydstra_xml_store>

从这个xml文本中,我想在&gt; site和&gt; / site&lt;之间提取属性值。在&#34; _&#34;(蓝色字体)中。例如&#34; G0010001&#34;,&#34; Sandover River - #7 Bore&#34; ...

这是我用过的代码

url="http://water.nt.gov.au/wgen/cache/anon/G0010001.xml?1484112860902?1484112861283" data=XML::xmlParse(readLines(url)) xpathSApply(data, "//webbatls/site[@station,@....]")

我能够成功解析xml文本。我在提取属性值方面遇到了困难。我的情况非常糟糕,请帮助我。

这是我调用XpathSApply函数后获得的输出

[[1]]
<site station="G0010001" parent="" stname="Sandover River - #7 Bore" shortname="Sandover R #7 Bore" mapname="" zone="53" easting="476064.2" northing="7552556.9" grdatum="MGA94" latitude="-22.131884543" longitude="134.767896023" lldatum="GDA94" posacc="" elev="12.658" elevdatum="" elevacc="01" local_map="" timezone="9.5" qquarter="" quarter="" section="" township="" range="" meridian="" active="False" owner="" commence="16/10/1968" cease="15/05/1974" stntype="SWG" region="5" orgcode="NTP" barcode="" category1="" category2="" category3="" category4="" category5="" category6="" category7="" category8="" category9="" category10="" category11="" category12="" category13="" category14="" category15="" category16="" category17="" category18="" category19="" category20="" spare1="" spare2="" enteredby="" checkedby="HYD" comment="" dbver41="" datecreate="30/12/1899" timecreate="0" usercreate="" datemod="09/12/2016" timemod="1111" usermod="BAILJ">
  <_decode_ station="Sandover R #7 Bore" parent="(None)" grdatum="Map Grid of Australia 1994" latitude="22&#xB0;07'54.8&quot;S" longitude="134&#xB0;46'04.4&quot;E" lldatum="Geodetic Datum of Australia 1994" posacc="Prec unknown" elevdatum="(unknown)" elevacc="Not Applicable" timezone="Offset of standard local time from GMT" meridian="Unspecified" owner="(None)" stntype="SW Gauging Station" region="NT Wide" orgcode="NT Water Resources" category1="(Not set)" category2="(Not set)" category3="(Not set)" category4="(unknown)" category5="Unknown" category6="Unknown" category7="Unknown" category8="Unknown" category9="Unknown" category10="Unknown" category11="(unknown)" category12="(unknown)" category13="(unknown)" category14="(unknown)" category15="(unknown)" category16="(unknown)" category17="(unknown)" category18="(unknown)" category19="(unknown)" category20="(unknown)" enteredby="(unknown)" checkedby="HYDMG &lt;Data imported by H"/>
</site>

2 个答案:

答案 0 :(得分:0)

将文本保存为例如“a”变量然后尝试这个:)

b&lt; -gsub('“','',a)

答案 1 :(得分:0)

我是那个问这个问题的人,在浏览了其他网络资源后我终于得到了解决方案。我想共享解决方案,因为这可能对面临同样问题的其他人有所帮助。

url="http://water.nt.gov.au/wgen/cache/anon/G0010001.xml?1484112860902?1484112861283"
    data=XML::xmlParse(readLines(url))
    dum1=(t(sapply(c("station",'stname','shortname','zone','latitude','longitude','lldatum','elev','commence','cease'), function(x) XML::xpathSApply(data, '//site', XML::xmlGetAttr, x))))

输出&#39; dum1&#39;包含&#34; station&#34;,&#39; stname&#39;,&#39; shortname&#39;,&#39; zone&#39;,&#39; latitude&#39;,& #39;经度&#39;&#39; lldatum&#39;&#39;海拔。&#39;&#39;开始&#39;&#39;停止&#39;

但我还需要一些属性值,从&gt; station到&gt; / station&lt;同样。为此我再次使用最后一行代码(相应地更改属性名称和Xpath)并将两个vec组合成一个向量。

dum2=(t(sapply(c("gauge",'datum','control','ctf','streamdist','maxgaug','maxgdate','catcharea'), function(x) XML::xpathSApply(data, '//station', XML::xmlGetAttr, x))))

    dat=cbind(dum1,dum2)

输出

dat
     station    stname                     shortname            zone latitude        longitude       lldatum elev     commence    
[1,] "G0010001" "Sandover River - #7 Bore" "Sandover R #7 Bore" "53" "-22.131884543" "134.767896023" "GDA94" "12.658" "16/10/1968"
     cease        gauge datum control           ctf     streamdist maxgaug maxgdate     catcharea
[1,] "15/05/1974" "0"   "GD"  "sandy river bed" "1.368" "0"        "0"     "30/12/1899" "5050"