Scraping with rvest - complete with NAs when tag is not present

Question

I want to parse this HTML: and get this elements from it:

a) p tag, with class: \"normal_encontrado\".
b) div with c

Answer 1

If the tag is not found, rvest returns a character(0). So assuming you will find at most one current and one regular price in each div.product_price, you can use this:

pacman::p_load("rvest", "dplyr")

get_prices <- function(node){
  r.precio.antes <- html_nodes(node, 'p.normal_encontrado') %>% html_text
  r.precio.actual <- html_nodes(node, 'div.price') %>% html_text

  data.frame(
    precio.antes = ifelse(length(r.precio.antes)==0, NA, r.precio.antes),
    precio.actual = ifelse(length(r.precio.actual)==0, NA, r.precio.actual), 
    stringsAsFactors=F
  )

}

doc <- read_html('test.html') %>% html_nodes("div.product_price")
lapply(doc, get_prices) %>%
  rbind_all

Edited: I misunderstood the input data, so changed the script to work with just a single html page.