#' ---
#' title: "Web scraping"
#' date: "2022-06-17"
#' author: "Jose https://ajuda.multifarm.top"
#' output:
#'   html_document:
#'    code_folding: show
#'    toc: yes
#'    toc_float:
#'      smooth_scroll: true
#'    df_print: paged
#'    highlight: zenburn
#' ---

#' remove objects

rm(list = ls())

#' Libraries
library(rvest)

#' Data

url <- 'https://www-remessaonline-com-br.cdn.ampproject.org/c/s/www.remessaonline.com.br/blog/agtech/amp/'

#'------------------------------------------------------------------------------
#'
#' ## Scraping a url
#'
#' ------------------------------------------------------------------------------

### Headings

u <- read_html(url)

class(u)

str(u)

u[[2]]

html_elements(u, "h1")

html_elements(u, "h2")

html_nodes(u, "h3") |> html_text2() |> data.table::data.table()

html_elements(u, "h4")

html_elements(u, "h5")

html_children(u)

nodes <- paste0('h', c(1:6))

?html_elements

### Paragraphs

pel <- html_elements(u, "p") |> html_text()

peli <- as.list(pel)

peli[[2]]

### List elements

html_nodes(u, "ul") |> html_text()

html_nodes(u, "li") |> html_text()