DataCamp Descriptions

Like the previous exercise, the code here is long since you are working with an entire web-crawling spider! But again, don't let the amount of code intimidate you, you have a handle on how spiders work now, and you are perfectly capable to complete the easy task for you here!

As in the previous exercise, we have created a function previewCourses which lets you preview the output of the spider, but you can always just explore the dictionary dc_dict too after you run the code.

In this exercise, you are asked to create a CSS Locator string direct to the text of the course description. All you need to know is that from the course page, the course description text is within a paragraph p element which belongs to the class course__description (two underlines).

This exercise is part of the course

Web Scraping in Python

View Course

Exercise instructions

Fill in the one blank below in the parse_pages method with a CSS Locator string which directs to the text within the paragraph p element which belongs to the class course__description.

NOTE: If you hit Run Code, you must Reset to Sample Code to successfully use Run Code again!!

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Import scrapy
import scrapy

# Import the CrawlerProcess: for running the spider
from scrapy.crawler import CrawlerProcess

# Create the Spider class
class DC_Description_Spider(scrapy.Spider):
  name = "dc_chapter_spider"
  # start_requests method
  def start_requests(self):
    yield scrapy.Request(url = url_short,
                         callback = self.parse_front)
  # First parsing method
  def parse_front(self, response):
    course_blocks = response.css('div.course-block')
    course_links = course_blocks.xpath('./a/@href')
    links_to_follow = course_links.extract()
    for url in links_to_follow:
      yield response.follow(url = url,
                            callback = self.parse_pages)
  # Second parsing method
  def parse_pages(self, response):
    # Create a SelectorList of the course titles text
    crs_title = response.xpath('//h1[contains(@class,"title")]/text()')
    # Extract the text and strip it clean
    crs_title_ext = crs_title.extract_first().strip()
    # Create a SelectorList of course descriptions text
    crs_descr = response.css( ____ )
    # Extract the text and strip it clean
    crs_descr_ext = crs_descr.extract_first().strip()
    # Fill in the dictionary
    dc_dict[crs_title_ext] = crs_descr_ext

# Initialize the dictionary **outside** of the Spider class
dc_dict = dict()

# Run the Spider
process = CrawlerProcess()
process.crawl(DC_Description_Spider)
process.start()

# Print a preview of courses
previewCourses(dc_dict)

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