1. Learn
    2. /
  2. Courses
    3. /
  3. Web Scraping in R

Exercise

Apply throttling to a multi-page crawler

The goal of this exercise is to get the coordinates of earth's three highest mountain peaks, together with their names.

You'll get this information from their corresponding Wikipedia pages, in real-time. In order not to stress Wikipedia too much, you'll apply throttling using the slowly() function. After each call to a Wikipedia page, your program should wait a small amount of time. Three pages of Wikipedia might not be that much, but the principle holds for any amount of scraping: be gentle and add wait time between requests.

You'll find the name of the peak within an element with the ID "firstHeading", while the coordinates are inside an element with class "geo-dms", which is a descendant of an element with ID "coordinates".

purrr has been preloaded and the URLs are contained in mountain_wiki_pages.

Instructions 1/3

undefined XP
    1
    2
    3
  • Construct a read_html() function that executes with a delay of a half second when executed in a loop.