Webscrape标题和列表到带有rvest的数据帧

那个页面有一个奇怪的结构,主表中有表。

我发现我的工作是重复( map_df() )父表的单元格(由 s4-wpcell-plain 类)。每个单元格都包含另一个表,但我们可以简单地提取所需内容,而不是依赖 html_table() .

library(tidyverse)    
library(rvest)
#> Loading required package: xml2


r <- read_html("http://www.secnav.navy.mil/fmc/fmb/Pages/Fiscal-Year-2019.aspx") %>% 
  html_node("#sharePointMainContent>div>table") %>% 
  html_nodes(".s4-wpcell-plain") %>% 
  map_df(~{
    heading <- .x %>% html_nodes('h3') %>% html_text() %>% str_trim()
    titles <- .x %>% html_nodes('li') %>% html_text()
    links <- .x %>% html_nodes('a') %>% html_attr("href")
    data_frame(heading, titles, links)
  })

r
#> # A tibble: 21 x 3
#>    heading                        titles                 links            
#>    <chr>                          <chr>                  <chr>            
#>  1 DEPARTMENT OF THE NAVY SUMMARY FY 19 DON Press Brief  http://www.secna…
#>  2 DEPARTMENT OF THE NAVY SUMMARY Supporting Exhibits    http://www.secna…
#>  3 DEPARTMENT OF THE NAVY SUMMARY Budget Highlights Book http://www.secna…
#>  4 DEPARTMENT OF THE NAVY SUMMARY The Bottom Line        http://www.secna…
#>  5 DEPARTMENT OF THE NAVY SUMMARY Report to Congress on… http://www.secna…
#>  6 DEPARTMENT OF THE NAVY SUMMARY Ship Building Plan SE… http://www.secna…
#>  7 MILITARY PERSONNEL PROGRAMS    Military Personnel, N… http://www.secna…
#>  8 MILITARY PERSONNEL PROGRAMS    Military Personnel, M… http://www.secna…
#>  9 MILITARY PERSONNEL PROGRAMS    Reserve Personnel, Na… http://www.secna…
#> 10 MILITARY PERSONNEL PROGRAMS    Reserve Personnel, Ma… http://www.secna…
#> # ... with 11 more rows

创建日期:2018-09-04 reprex package (v0.2.0版)。