Xml 使用XPath检索节点的属性和标识符中带有冒号的属性

在R中使用XPathSapply，我尝试在edgar:url属性中检索url：

<edgar:xbrlFile edgar:sequence="3" edgar:file="edgr-2004_10k.xml" edgar:type="EX-100.INS" edgar:size="25257" edgar:description="" edgar:url="http://www.sec.gov/Archives/edgar/data/1080224/000127528705001434/edgr-2004_10k.xml" />

我尝试了以下几种变体：

url <- "http://www.sec.gov/Archives/edgar/monthly/xbrlrss-2005-04.xml"
data <- getURL(url)
doc <- xmlParse(data)
url <- xpathSApply(doc, "//item/*[name()='edgar:xbrlFiling']", xmlValue)

---

url使用
XML
和使用
xml2
（暂时只能安装github）都非常简单

XML
：

xpathSApply(doc, "//edgar:xbrlFile", xmlGetAttr, "edgar:url", namespaces="edgar")

xml2
：

library(xml2)
dat <- read_xml(url)

dat %>% 
  xml_find_all("//edgar:xbrlFile", ns=xml_ns(dat)) %>% 
  xml_attr("edgar:url", ns=xml_ns(dat))

我知道它必须比我做的要简单。谢谢可能重复：不是重复。问题是节点和属性是否有冒号。
library(xml2)
dat <- read_xml(url)

dat %>% 
  xml_find_all("//edgar:xbrlFile", ns=xml_ns(dat)) %>% 
  xml_attr("edgar:url", ns=xml_ns(dat))

##  [1] "http://www.sec.gov/Archives/edgar/data/1080224/000127528705001434/eo2425.txt"            
##  [2] "http://www.sec.gov/Archives/edgar/data/1080224/000127528705001434/eo2425ex991.txt"       
##  [3] "http://www.sec.gov/Archives/edgar/data/1080224/000127528705001434/edgr-2004_10k.xml"     
##  [4] "http://www.sec.gov/Archives/edgar/data/1080224/000127528705001434/edgr-20050228.xsd"     
##  [5] "http://www.sec.gov/Archives/edgar/data/1080224/000127528705001434/edgr-20050228_cal.xml" 
##  [6] "http://www.sec.gov/Archives/edgar/data/1080224/000127528705001434/edgr-20050228_lab.xml" 
##  [7] "http://www.sec.gov/Archives/edgar/data/1080224/000127528705001434/edgr-20050228_pre.xml" 
##  [8] "http://www.sec.gov/Archives/edgar/data/29669/000119312505068717/d8k.htm"                 
##  [9] "http://www.sec.gov/Archives/edgar/data/29669/000119312505068717/xrrd-20050331.xml"       
## [10] "http://www.sec.gov/Archives/edgar/data/29669/000119312505068717/xrrd-20050331.xsd"       
## [11] "http://www.sec.gov/Archives/edgar/data/29669/000119312505068717/xrrd-20050331_cal.xml"   
## [12] "http://www.sec.gov/Archives/edgar/data/29669/000119312505068717/xrrd-20050331_lab.xml"   
## [13] "http://www.sec.gov/Archives/edgar/data/29669/000119312505068717/xrrd-20050331_pre.xml"   
## [14] "http://www.sec.gov/Archives/edgar/data/13610/000095012305004029/bne-20050404_8kfinal.htm"
## [15] "http://www.sec.gov/Archives/edgar/data/13610/000095012305004029/bne-20041231er.xml"      
## [16] "http://www.sec.gov/Archives/edgar/data/13610/000095012305004029/bne-20050307er.xsd"      
## [17] "http://www.sec.gov/Archives/edgar/data/13610/000095012305004029/bne-20050307er_pre.xml"  
## [18] "http://www.sec.gov/Archives/edgar/data/13610/000095012305004029/bne-20050307er_lab.xml"  
## [19] "http://www.sec.gov/Archives/edgar/data/13610/000095012305004029/bne-20050307er_cal.xml"