我使用 R 中的 xml2 包来访问 xml 数据,发现它在不同的 xml_documents 上表现不同。
在这个宠物的例子中
library(xml2)
doc <- read_xml( "<MEMBERS>
<CUSTOMER>
<ID>178</ID>
<FIRST.NAME>Alvaro</FIRST.NAME>
<LAST.NAME>Juarez</LAST.NAME>
<ADDRESS>123 Park Ave</ADDRESS>
<ZIP>57701</ZIP>
</CUSTOMER>
<CUSTOMER>
<ID>934</ID>
<FIRST.NAME>Janette</FIRST.NAME>
<LAST.NAME>Johnson</LAST.NAME>
<ADDRESS>456 Candy Ln</ADDRESS>
<ZIP>57701</ZIP>
</CUSTOMER>
</MEMBERS>")
doc
{xml_document}
<MEMBERS>
[1] <CUSTOMER>\n <ID>178</ID>\n <FIRST.NAME>Alvaro</FIRST.NAME>\n <LAST.NAME>Juarez</LAST.NAME>\n <ADDRESS>12 ...
[2] <CUSTOMER>\n <ID>934</ID>\n <FIRST.NAME>Janette</FIRST.NAME>\n <LAST.NAME>Johnson</LAST.NAME>\n <ADDRESS> ...
我可以运行以下代码
xml_find_all(doc, "//FIRST.NAME")
{xml_nodeset (2)}
[1] <FIRST.NAME>Alvaro</FIRST.NAME>
[2] <FIRST.NAME>Janette</FIRST.NAME>
给我预期的输出(查找带有“FIRST.NAME”标签的所有节点)。
但是,如果我执行相同的操作this https://www.dropbox.com/s/37ht3e9c4mzshkb/uniprot_subset.xml?dl=0xml 文件:
example <- read_xml(file.path("~/Downloads", "uniprot_subset.xml"))
> example
{xml_document}
<uniprot>
[1] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2011-06-28" modified="2019-01-16" version="35">\n <accession>Q6GZX4</accession>\n <name>001R_FRG3G</name>\n <protein>\n <recommendedName>\n <fullName>Putative tr ...
[2] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2011-06-28" modified="2019-01-16" version="36">\n <accession>Q6GZX3</accession>\n <name>002L_FRG3G</name>\n <protein>\n <recommendedName>\n <fullName>Uncharacter ...
[3] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2009-06-16" modified="2018-06-20" version="22">\n <accession>Q197F8</accession>\n <name>002R_IIV3</name>\n <protein>\n <recommendedName>\n <fullName>Uncharacteri ...
[4] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2009-06-16" modified="2017-09-27" version="18">\n <accession>Q197F7</accession>\n <name>003L_IIV3</name>\n <protein>\n <recommendedName>\n <fullName>Uncharacteri ...
[5] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2011-06-28" modified="2019-01-16" version="31">\n <accession>Q6GZX2</accession>\n <name>003R_FRG3G</name>\n <protein>\n <recommendedName>\n <fullName>Uncharacter ...
[6] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2011-06-28" modified="2017-09-27" version="29">\n <accession>Q6GZX1</accession>\n <name>004R_FRG3G</name>\n <protein>\n <recommendedName>\n <fullName>Uncharacter ...
[7] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2009-06-16" modified="2017-09-27" version="24">\n <accession>Q197F5</accession>\n <name>005L_IIV3</name>\n <protein>\n <recommendedName>\n <fullName>Uncharacteri ...
[8] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2011-06-28" modified="2019-01-16" version="38">\n <accession>Q6GZX0</accession>\n <name>005R_FRG3G</name>\n <protein>\n <recommendedName>\n <fullName>Uncharacter ...
[9] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2009-06-16" modified="2019-01-16" version="44">\n <accession>Q91G88</accession>\n <name>006L_IIV6</name>\n <protein>\n <recommendedName>\n <fullName>Putative Kil ...
[10] <entry xmlns="http://uniprot.org/uniprot" dataset="Swiss-Prot" created="2011-06-28" modified="2017-09-27" version="27">\n <accession>Q6GZW9</accession>\n <name>006R_FRG3G</name>\n <protein>\n <recommendedName>\n <fullName>Uncharacter ...
它的行为不同
xml_find_all(example, "//accession")
{xml_nodeset (0)}
基本上,它不会找到任何带有“accession”标签的节点,即使它们存在并且可以通过不同的函数访问,例如使用
xml_children(xml_children(example)[1])[1]
{xml_nodeset (1)}
[1] <accession>Q6GZX4</accession>
谁能告诉我为什么 xml_find_all 函数在后一个示例中找不到任何节点?