我怎么错了 rvest 包？

Question

我在使用 r 中的 rvest 包进行抓取时遇到了问题。我试图从网站上收集信息并创建一个数据框，其中包含循环内指定的向量。

除非我使用循环函数，否则我会得到正确的数据。谁能告诉我以下代码有什么问题吗？

我的预感是我未能组合向量...

library(rvest)
library(dplyr)
library(tidyr)
library(stringr)
library(stringi)


#This is the URL from which I would like to get information.
source_url <- "https://go2senkyo.com/local/senkyo/"
senkyo <- data.frame() 

*start for loop
for (i in 50:60) { 

target_page <- paste0(source_url, i)
recall_html <- read_html(source_url, encoding = "UTF-8")


prefecture <- recall_html %>%
        html_nodes(xpath='//*[contains(concat( " ", @class, " " ), concat( " ", "column_ttl_small", " " ))]') %>%
        html_text()

city <- recall_html %>%
    html_nodes(xpath='//*[contains(concat( " ", @class, " " ), concat( " ", "column_ttl", " " ))]') %>%
    html_text()
city <- trimws(gsub("[\r\n]", "", city )) %>% unlist() %>% str


candidate <- recall_html %>%
    html_nodes(xpath='//*[contains(concat( " ", @class, " " ), concat( " ", "m_senkyo_result_table", " " ))]') %>%
    html_text()
candidate  <- trimws(gsub("[\r\n\t]", "", candidate ))

all <- recall_html %>%
    html_nodes(xpath='//td') %>%
    html_text() 
all <- trimws(gsub("[\r\n\t]", "", all))

election_day <- all[1]
turnout  <- all[2]
magnitude_candidates <- all[3] 
notificationday <- all[4]
turnout_lasttime <- all[5]
others <- all[6]



senkyo2 <- cbind(prefecture, city, candidate, election_day, turnout, magnitude_candidates, notificationday,
        turnout_lasttime, others) 
senkyo  <- rbind(senkyo , senkyo2) 

}

Answer 1

这似乎是你的错误：

recall_html <- read_html(source_url, encoding = "UTF-8")

应该使用target_page而不是source_url

recall_html <- read_html(target_page, encoding = "UTF-8")

我怎么错了 rvest 包？

How am I wrong with rvest package?

r

web-scraping

rvest