在R中使用map()将列表应用于web抓取函数

map(.x, .f, ...)

library(rvest)
library(purrr)

# 示例URL列表
urls <- list(
  "https://example.com/page1",
  "https://example.com/page2",
  "https://example.com/page3"
)

# 定义web抓取函数
scrape_page <- function(url) {
  page <- read_html(url)
  title <- page %>% html_nodes("title") %>% html_text()
  return(title)
}

# 使用map()函数应用web抓取函数
titles <- map(urls, scrape_page)

# 打印结果
print(titles)

scrape_page <- function(url) {
  tryCatch({
    page <- read_html(url)
    title <- page %>% html_nodes("title") %>% html_text()
    return(title)
  }, error = function(e) {
    return(paste("Error:", url, e))
  })
}

scrape_page <- function(url) {
  page <- read_html(url)
  if (length(page %>% html_nodes("title")) > 0) {
    title <- page %>% html_nodes("title") %>% html_text()
  } else {
    title <- "Title not found"
  }
  return(title)
}