Question

我正在尝试复制this tutorial on rvest here。但是，一开始我已经遇到了问题。这是我正在使用的代码

library(rvest)
#Specifying the url for desired website to be scrapped
url <- 'https://www.nytimes.com/section/politics'

#Reading the HTML code from the website - headlines
webpage <- read_html(url)
headline_data <- html_nodes(webpage,'.story-link a, .story-body a')

当我看着headline_data返回时的结果

{xml_nodeset (0)}

但是在本教程中，它返回长度为48的列表

{xml_nodeset (48)}

有任何差异的原因吗？

Answer 1

如注释中所述，没有要搜索的具有指定类的元素。

首先，根据当前标签，您可以使用以下标题：

library(rvest)
library(dplyr)
url <- 'https://www.nytimes.com/section/politics'

url %>%
  read_html() %>%
  html_nodes("h2.css-l2vidh a") %>%
  html_text()

#[1] "Trump’s Secrecy Fight Escalates as Judge Rules for Congress in Early Test"                    
#[2] "A Would-Be Trump Aide’s Demands: A Jet on Call, a Future Cabinet Post and More"               
#[3] "He’s One of the Biggest Backers of Trump’s Push to Protect American Steel. And He’s Canadian."
#[4] "Accountants Must Turn Over Trump’s Financial Records, Lower-Court Judge Rules"

并获取您可以做的那些标题的单独URL

url %>%
  read_html() %>%
  html_nodes("h2.css-l2vidh a") %>%
  html_attr("href") %>%
  paste0("https://www.nytimes.com", .)

#[1] "https://www.nytimes.com/2019/05/20/us/politics/mcgahn-trump-congress.html"                                                                   
#[2] "https://www.nytimes.com/2019/05/20/us/politics/kris-kobach-trump.html"                                                                       
#[3] "https://www.nytimes.com/2019/05/20/us/politics/hes-one-of-the-biggest-backers-of-trumps-push-to-protect-american-steel-and-hes-canadian.html"
#[4] "https://www.nytimes.com/2019/05/20/us/politics/trump-financial-records.html"

Rvest：标题返回空列表

1 个答案: