how to do for loop on that code in R. I want to do web scraping -
i have lot of urls address want apply 2 lines of code under:
a <- htmltreeparse("url address",useinternal=t,encoding='utf-8') d <- xpathsapply(a,"//div[@class='text']",xmlvalue)
how it?
i tried it:
urls <- read.table("file.txt") #txt file url's for(i in 1:200){ <- 1:200 c <- 1:200 d <- 1:200 a[i]<-as.character(urls[i,]) c[i] <- htmltreeparse(a[i],useinternal=t,encoding='utf-8') d[i] <- xpathsapply(c[i],"//div[@class='text']",xmlvalue) }
my problem in code above xpathsapply
function utilize object of class xmlinternaldocument
, c[i]
should of class. don't know how can that
try:
urls<-read.table("file.txt") #txt file url's <- c() c <- c() d <- c() for(i in 1:200){ a[i]<- as.character(urls[i,]) c <- htmltreeparse(a[i],useinternal=t,encoding='utf-8') d[i]<- xpathsapply(c,"//div[@class='text']",xmlvalue) }
r for-loop web-scraping
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