r在网页中抓取（带循环）

Question

我需要从this link中抓取数据并将表格保存为csv。我现在拥有的一切：我 废能利用rvest第一页，第二页，并使用此代码保存这些表：

library(rvest) 
webpage <- read_html("https://bra.areacodebase.com/number_type/M?page=0") 
data <- webpage %>% 
    html_nodes("table") %>% 
    .[[1]] %>% 
    html_table() 
url<- "https://bra.areacodebase.com/number_type/M?page=0" 
webpage2<- html_session(url) %>% follow_link(css = ".pager-next a") 
data2 <- webpage %>% 
html_nodes("table") %>% 
.[[1]] %>% 
    html_table() 
data_all <- rbind(data, data2) 
write.table(data_all, "df_data.csv", sep = ";", na = "", quote = FALSE, row.names = FALSE) 

#result<- lapply(webpage, %>% follow_link(css = ".pager-next a")) 
#data_all <- rbind(data:data2) 

但是，我想不出如何运行循环。

Answer 1

您可以进入到下一个环节与follow_link或通过网址直接获取页：

webpage <- "https://bra.areacodebase.com/number_type/M?page=0" 

for(i in 2:5089) { 
    data <- read_html(webpage) %>% 
    html_nodes("table") %>% 
    .[[1]] %>% 
    html_table() 

    webpage <- html_session(webpage) %>% follow_link(css = ".pager-next a") %>% .[["url"]] 
} 

或者直接网址：

for(i in 0:5089) { 
    webpage <- read_html(paste0("https://bra.areacodebase.com/number_type/M?page=", i)) 
    data <- webpage %>% 
    html_nodes("table") %>% 
    .[[1]] %>% 
    html_table() 
}