如何使用 R 的 XML 包编写 RSS 格式的 XML 文档

Question

我正在尝试使用R的XML包创建RSS文档，但是我遇到了麻烦。下面是我使用的代码:

df <- data.frame(Labels <- c("Label_1"),
Values <- c("Value_1")
)
# CREATE XML FILE
doc = newXMLDoc()
root = newXMLNode("rss", doc = doc)
# WRITE XML NODES AND DATA
channel = newXMLNode("channel", parent = root)
title = newXMLNode("title","Metrics", parent = channel)
for (i in 1:nrow(df)){
prodNode = newXMLNode("Metric", parent = channel)

# APPEND TO PRODUCT NODE
newXMLNode("description", df$Labels[i], parent = prodNode)
newXMLNode("item", df$Values[i], parent = prodNode)
}
# OUTPUT XML CONTENT TO CONSOLE
print(doc)
# OUTPUT XML CONTENT TO FILE
saveXML(doc, file="RSS_Output.xml")

这给了我以下输出，它不能与RSS解析器一起工作，原因之一是根节点错误。有什么更清晰地生成RSS文件的方法吗?

<?xml version="1.0"?>
<rss>
<channel>
<title>Metrics</title>
<Metric>
<description>Label_1</description>
<item>Value_1</item>
</Metric>
</channel>
</rss>

Answer 1

您混合了Metric和item节点。根据RSS规范(参见https://www.w3schools.com/xml/xml_rss.asp)，channel包含1个或多个item元素

df <- data.frame(Labels <- c("Label_1"),
Values <- c("Value_1")
)
# CREATE XML FILE
doc = newXMLDoc()
root = newXMLNode("rss", doc = doc)
# WRITE XML NODES AND DATA
channel = newXMLNode("channel", parent = root)
title = newXMLNode("title","Metrics", parent = channel)
for (i in 1:nrow(df)){
prodNode = newXMLNode("item", parent = channel)

# APPEND TO PRODUCT NODE
newXMLNode("description", df$Labels[i], parent = prodNode)
newXMLNode("metric", df$Values[i], parent = prodNode)
}
# OUTPUT XML CONTENT TO CONSOLE
print(doc)
# OUTPUT XML CONTENT TO FILE
saveXML(doc, file="RSS_Output.xml")

<?xml version="1.0"?>
<rss>
<channel>
<title>Metrics</title>
<item>
<description>Label_1</description>
<metric>Value_1</metric>
</item>
</channel>
</rss>