procedure

parameter can be <name>, <name>, ... 

def <name> (<parameters>):

<block>

page =  ... contents of some web page ...

start_link = page.find('<a href=')

start_quote = page.find('"',start_link)

end_quote=gape.find('"',start_quote+1)

url = page[start_quote+1:end_quote]

print url # first url on the page

# repeat

page = page[end_quote:]                           # page 값을 update

start_link = page.find('<a href=')

start_quote = page.find('"',start_link)

end_quote= page.find('"',start_quote+1)

url = page[start_quote+1:end_quote]

print url # second url on the page

보라색 부분을 procedure로 만들기

procedure name : get_next_target

input : string giving contents of the rest of the web page

output : url, end_quote

    ↓ representing the string (page)

def get_next_target( s ): 

start_link = s.find('<a href=')

start_quote = s.find('"',start_link)

end_quote=s.find('"',start_quote+1)

url = s[start_quote+1:end_quote]

return url, end_quote