如何废弃70页的html数据?我正在看这个question但我仍然坚持一般方法部分的功能。
#attempt
library(purrr)
url_base <-"https://secure.capitalbikeshare.com/profile/trips/QNURCMF2Q6"
map_df(1:70, function(i) {
cat(".")
pg <- read_html(sprintf(url_base, i))
data.frame( startd=html_text(html_nodes(pg, ".ed-table__col_trip-start-date")),
endd=html_text(html_nodes(pg,".ed-table__col_trip-end-date")),
duration=html_text(html_nodes(pg, ".ed-table__col_trip-duration"))
)
}) -> table
#attempt 2 (with just one data column)
url_base <-"https://secure.capitalbikeshare.com/profile/trips/QNURCMF2Q6"
map_df(1:70, function(i) {
page %>% html_nodes(".ed-table__item_odd") %>% html_text()
}) -> table
答案 0 :(得分:0)
@ jso1226,我不确定你所引用的答案中发生了什么,所以我提供了一个与你想要做的非常相似的例子。
这是:转到网页收集信息,添加数据框然后转到下一页。
我使用此代码创建来跟踪我在此处发布的回复到stackoverflow:
login<-"https://stackoverflow.com/users/login?ssrc=head&returnurl=http%3a%2f%2fstackoverflow.com%2f"
library(rvest)
pgsession<-html_session(login)
pgform<-html_form(pgsession)[[2]]
filled_form<-set_values(pgform, email="*****", password="*****")
submit_form(pgsession, filled_form)
#pre allocate the final results dataframe.
results<-data.frame()
for (i in 1:5)
{
url<-"http://stackoverflow.com/users/**********?tab=answers&sort=activity&page="
url<-paste0(url, i)
page<-jump_to(pgsession, url)
#collect question votes and question title
summary<-html_nodes(page, "div .answer-summary")
question<-matrix(html_text(html_nodes(summary, "div"), trim=TRUE), ncol=2, byrow = TRUE)
#find date answered, hyperlink and whether it was accepted
dateans<-html_node(summary, "span") %>% html_attr("title")
hyperlink<-html_node(summary, "div a") %>% html_attr("href")
accepted<-html_node(summary, "div") %>% html_attr("class")
#create temp results then bind to final results
rtemp<-cbind(question, dateans, accepted, hyperlink)
results<-rbind(results, rtemp)
}
#Dataframe Clean-up
names(results)<-c("Votes", "Answer", "Date", "Accepted", "HyperLink")
results$Votes<-as.integer(as.character(results$Votes))
results$Accepted<-ifelse(results$Accepted=="answer-votes default", 0, 1)
这种情况下的循环仅限于5页,需要根据您的应用进行更改。我用******替换了用户特定的值,希望这将为您提供一些指导。