Self Referencing is Classy
You probably have noticed that within the spider class, we always input the argument self
in the start_requests
and parse
methods (just look in the sample code in this exercise!). This allows us to reference between methods within the class. That is, if we want to refer to the method parse
within the start_requests
method, we would need to write self.parse
rather than just parse
; what writing self
does is tell the code: "Look in the same class as start_requests
for a method called parse
to use."
In this exercise you will get a chance to play with this "self referencing".
This exercise is part of the course
Web Scraping in Python
Exercise instructions
- Fill in the required
scrapy
object into the classYourSpider
needed to create thescrapy
spider. - Pass the string argument
"Hello World!"
to fill in the blank in thestart_requests
method to use theprint_msg
method.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Import scrapy library
import scrapy
# Create the spider class
class YourSpider( ____ ):
name = "your_spider"
# start_requests method
def start_requests( self ):
self.print_msg( ____ )
# parse method
def parse( self, response ):
pass
# print_msg method
def print_msg( self, msg ):
print( "Calling start_requests in YourSpider prints out:", msg )
# Inspect Your Class
inspect_class( YourSpider )