将xml_nodeset转换为data.frame

我在用rvest.我想将结果转换为数据框:

> links <- pgsession %>% jump_to(urls[2])  %>%  read_html() %>% html_nodes("a")    
> links
{xml_nodeset (114)}
 [1] Date
 [2] Kennwort ändern
 [3] Benutzernamen ändern
 [4] Abmelden
...    

我使用以下方法:

library(plyr)
ldply(xmlToList(links), data.frame)
Error in UseMethod("xmlSApply") : 
    no applicable method for 'xmlSApply' applied to an object of class "xml_nodeset"
df1 <- data.frame(character(13000))
df1 <- rbind(df1, data.frame(links ))# append to data.frame

但是,我收到一个错误:

Error in UseMethod("xmlSApply") : 
    no applicable method for 'xmlSApply' applied to an object of class "xml_nodeset"

有什么建议我做错了吗？

感谢您的回复!

这将从链接中获取所有属性tbl_df.bind_rows让你"免费"填写:

library(rvest)
library(dplyr)

pg <- read_html("https://en.wikipedia.org/wiki/Main_Page")
links <- html_nodes(pg, "a")
bind_rows(lapply(xml_attrs(links), function(x) data.frame(as.list(x), stringsAsFactors=FALSE)))

## Source: local data frame [310 x 10]
## 
##       id                         href                  title class   dir accesskey   rel  lang hreflang style
##    (chr)                        (chr)                  (chr) (chr) (chr)     (chr) (chr) (chr)    (chr) (chr)
## 1    top                           NA                     NA    NA    NA        NA    NA    NA       NA    NA
## 2     NA                     #mw-head                     NA    NA    NA        NA    NA    NA       NA    NA
## 3     NA                    #p-search                     NA    NA    NA        NA    NA    NA       NA    NA
## 4     NA              /wiki/Wikipedia              Wikipedia    NA    NA        NA    NA    NA       NA    NA
## 5     NA           /wiki/Free_content           Free content    NA    NA        NA    NA    NA       NA    NA
## 6     NA           /wiki/Encyclopedia           Encyclopedia    NA    NA        NA    NA    NA       NA    NA
## 7     NA /wiki/Wikipedia:Introduction Wikipedia:Introduction    NA    NA        NA    NA    NA       NA    NA
## 8     NA     /wiki/Special:Statistics     Special:Statistics    NA    NA        NA    NA    NA       NA    NA
## 9     NA       /wiki/English_language       English language    NA    NA        NA    NA    NA       NA    NA
## 10    NA            /wiki/Portal:Arts            Portal:Arts    NA    NA        NA    NA    NA       NA    NA
## ..   ...                          ...                    ...   ...   ...       ...   ...   ...      ...   ...

或者,您可以使用purrr:

library(rvest)
library(purrr)

pg <- read_html("https://en.wikipedia.org/wiki/Main_Page")
html_nodes(pg, "a") %>% 
  map(xml_attrs) %>% 
  map_df(~as.list(.))

## # A tibble: 342 × 10
##       id                         href                  title class   dir accesskey   rel hreflang  lang style
##                                                            
## 1    top                                                                 
## 2                        #mw-head                                        
## 3                       #p-search                                        
## 4                 /wiki/Wikipedia              Wikipedia                     
## 5              /wiki/Free_content           Free content                     
## 6              /wiki/Encyclopedia           Encyclopedia                     
## 7    /wiki/Wikipedia:Introduction Wikipedia:Introduction                     
## 8        /wiki/Special:Statistics     Special:Statistics                     
## 9          /wiki/English_language       English language                     
## 10              /wiki/Portal:Arts            Portal:Arts                     
## # ... with 332 more rows

我认为这更具功能性和整体清洁方法.