如何使用 r 背心从网站上抓取所有页面 (1,2,3,.....n) [英] how to scrape all pages (1,2,3,.....n) from a website using r vest

问题描述

# 我想读取 .html 文件列表以提取数据.感谢您的帮助.

# I would like to read the list of .html files to extract data. Appreciate your help.

library(rvest)
library(XML)
library(stringr)
library(data.table)
library(RCurl)

u0 <- "https://www.r-users.com/jobs/"
u1 <- read_html("https://www.r-users.com/jobs/")
download_folder <- ("C:/R/BNB/")
pages <- html_text(html_node(u1, ".results_count"))
Total_Pages <- substr(pages, 4, 7)
TP <- as.numeric(Total_Pages)
# reading first two pages, writing them as separate .html files
for (i in 1:TP) {
  url <- paste(u0, "page=/", i, sep = "")
  download.file(url, paste(download_folder, i, ".html", sep = ""))
  #create html object
  html <- html(paste(download_folder, i, ".html", sep = ""))
}

推荐答案

这是一个潜在的解决方案:

Here is a potential solution:

library(rvest)
library(stringr)

u0 <- "https://www.r-users.com/jobs/"
u1 <- read_html("https://www.r-users.com/jobs/")
download_folder <- getwd()  #note change in output directory

TP<-max(as.integer(html_text(html_nodes(u1,"a.page-numbers"))), na.rm=TRUE)

# reading first two pages, writing them as separate .html files 
for (i in 1:TP ) {
  url <- paste(u0,"page/",i, "/", sep="")
  print(url)
  download.file(url,paste(download_folder,i,".html",sep=""))
  #create html object
  html <- read_html(paste(download_folder,i,".html",sep=""))
}

我在 html 中找不到 .result-count 类，所以我寻找 page-numbers 类并选择最高的返回值.此外，函数 html 已被弃用，因此我将其替换为 read_html.祝你好运

I could not find the class .result-count in the html, so instead I looked for the page-numbers class and pick the highest returned value. Also, the function html is deprecated thus I replaced it with read_html. Good luck

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