Rvest返回零列表

Question

我想使用rvest从网络上下载论文的所有链接/标题。我使用了以下脚本，但列表不是零。有什么建议么？

图书馆（RVest）

1。下载HTML并使用read_html（）将其转换为XML文件

纸张<-read_html（“ https://papers.ssrn.com/sol3/JELJOUR_Results.cfm?npage=1&form_name=journalBrowse&journal_id=1475407&Network=no&lim=false”）

2。使用html_nodes（）提取特定的节点

标题<-html_nodes（文件，“ span.optClickTitle”）

Answer 1

您很亲密，请尝试使用.optClickTitle而不是span.optClickTitle：

library(magrittr)
library(tibble)
library(rvest)
#> Lade nötiges Paket: xml2

url <- "https://papers.ssrn.com/sol3/JELJOUR_Results.cfm?npage=1&form_name=journalBrowse&journal_id=1475407&Network=no&lim=false"
raw <- read_html(url)

parse_link <- function(x) {
  tibble(title = html_text(x),
         link = html_attr(x = x, name = "href"))
}

raw %>%
  html_nodes(".optClickTitle") %>%
  parse_link()
#> # A tibble: 60 x 2
#>    title                                            link                  
#>    <chr>                                            <chr>                 
#>  1 The Nature of Man                                https://ssrn.com/abst…
#>  2 The Dynamics of Crowdfunding: An Exploratory St… https://ssrn.com/abst…
#>  3 Some Simple Economics of the Blockchain          https://ssrn.com/abst…
#>  4 "Some Simple Economics of the Blockchain\r\n\t\… https://ssrn.com/abst…
#>  5 "Some Simple Economics of the Blockchain\r\n\t\… https://ssrn.com/abst…
#>  6 Bitcoin: An Innovative Alternative Digital Curr… https://ssrn.com/abst…
#>  7 Piracy and Box Office Movie Revenues: Evidence … https://ssrn.com/abst…
#>  8 The sharing economy: Why people participate in … https://ssrn.com/abst…
#>  9 Consumer Acceptance and Use of Information Tech… https://ssrn.com/abst…
#> 10 What Makes Online Content Viral?                 https://ssrn.com/abst…
#> # ... with 50 more rows

^{由reprex package（v0.2.1）于2018-09-28创建}