R selenium方法下载不同年份的数据

Question

以下代码是在我之前在同一平台上的一个问题中编写的。我必须下载 2020 年的数据，但是一旦在给定 Web 链接的右侧列上单击 2020 年，URL 就不会改变。该代码在 Firefox 上打开 2020 页面，但未在系统中下载所需文件（2020 文件）。它正在下载我不需要的 2021 文件。我无法弄清楚这个问题。 我正在处理的 URL 是：https://www.rbi.org.in/scripts/AnnualPublications.aspx?head=Handbook%20of%20Statistics%20on%20Indian%20Economy 代码是：

 library(tidyverse)
      library(stringr)
      library(purrr)
      library(rvest)
      library(RSelenium)
      
      rD <- rsDriver(browser="firefox", port=4567L, verbose=F)
      remDr <- rD[["client"]]
      
      remDr$navigate("https://www.rbi.org.in/scripts/AnnualPublications.aspx?head=Handbook+of+Statistics+on+Indian+Economy")
elem<- remDr$findElement(using = "link text", "2020")
      elem$clickElement()
      page <- remDr$getPageSource()[[1]]
      read_html(page) -> html
      html %>%
        html_nodes("a") %>%  
        html_attr("href") %>% 
        str_subset("\\.PDF") -> urls
      urls %>% str_split(.,'/') %>% unlist() %>% str_subset("\\.PDF") -> filenames
    
      for(u in 1:length(urls)) 
      {
        cat(paste('downloading: ', u, ' of ', length(urls)))
        download.file(urls[u], filenames[u], mode='wb')
      }
      system("taskkill /im java.exe /f", intern=FALSE, ignore.stdout=FALSE)

Answer 1

您可以通过获取手册名称来检查您是否在正确的页面上，

你现在是 2021 年

remDr$navigate("https://www.rbi.org.in/scripts/AnnualPublications.aspx?head=Handbook+of+Statistics+on+Indian+Economy")
remDr$getPageSource()[[1]] %>% 
  read_html() %>% html_nodes(xpath = '//*[@id="accordion"]/table[2]/tbody/tr[2]/td[1]/text()[1]') %>% html_text()
[1] "Handbook of Statistics on the Indian Economy, 2020-21 "

现在是 2020 年

elem<- remDr$findElement(using = "link text", "2020")
elem$clickElement()
remDr$getPageSource()[[1]] %>% 
  read_html() %>% html_nodes(xpath = '//*[@id="accordion"]/table[2]/tbody/tr[2]/td[1]/text()[1]') %>% html_text()
  [1] "Handbook of Statistics on Indian Economy 2019-20 "

编辑：-

library(tidyverse)
library(rvest)
library(RSelenium)

启动浏览器

rD <- rsDriver(browser="firefox", port=4567L, verbose=F)
remDr <- rD[["client"]]

加载网页

remDr$navigate("https://www.rbi.org.in/scripts/AnnualPublications.aspx?head=Handbook+of+Statistics+on+Indian+Economy")

点击年份2020。确保您获得正确年份的数据。

remDr$findElement(using = "link text", "2020")$clickElement()
remDr$getPageSource()[[1]] %>% 
  read_html() %>% html_nodes(xpath = '//*[@id="accordion"]/table[2]/tbody/tr[2]/td[1]/text()[1]') %>% html_text()

[1] "Handbook of Statistics on the Indian Economy, 2020-21 "

获取pdf名称、url并开始下载

urls =  remDr$getPageSource()[[1]] %>% read_html() %>% 
  html_nodes("a") %>%  
  html_attr("href") %>% 
  str_subset("\\.PDF")

filenames = urls %>% str_split(.,'/') %>% unlist() %>% str_subset("\\.PDF")

for(u in 1:length(urls)){
  cat(paste('downloading: ', u, ' of ', length(urls)))
  download.file(urls[u], filenames[u], mode='wb')
}