Web scraping w Pythonie

Importowanie danych w Pythonie – poziom średniozaawansowany

Hugo Bowne-Anderson

Data Scientist at DataCamp

HTML

Mieszanka danych nieustrukturyzowanych i ustrukturyzowanych
Dane ustrukturyzowane:
- Posiadają z góry określony model danych, lub
- Są zorganizowane w określony sposób
Dane nieustrukturyzowane: żadna z tych właściwości

ch_1_3.008.png

BeautifulSoup

Parsowanie i wyodrębnianie danych ustrukturyzowanych z HTML

ch_1_3.011.png

Porządkowanie „zupy tagów" i ekstrakcja informacji

BeautifulSoup

from bs4 import BeautifulSoup
import requests
url = 'https://www.crummy.com/software/BeautifulSoup/'
r = requests.get(url)
html_doc = r.text
soup = BeautifulSoup(html_doc)

Sformatowana zupa

print(soup.prettify())

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/transitional.dtd">
<html>
 <head>
  <meta content="text/html; charset=utf-8" http-equiv="Content-Type"/>
  <title>
   Beautiful Soup: We called him Tortoise because he taught us.
  </title>
  <link href="mailto:[email protected]" rev="made"/>
  <link href="/nb/themes/Default/nb.css" rel="stylesheet" type="text/css"/>
  <meta content="Beautiful Soup: a library designed for screen-scraping HTML and XML." name="Description"/>
  <meta content="Markov Approximation 1.4 (module: leonardr)" name="generator"/>
  <meta content="Leonard Richardson" name="author"/>
 </head>
 <body alink="red" bgcolor="white" link="blue" text="black" vlink="660066">
  <img align="right" src="10.1.jpg" width="250"/>
  <br/>
  <p>

Eksploracja BeautifulSoup

Wiele dostępnych metod, m.in.:

print(soup.title)

<title>Beautiful Soup: We called him Tortoise because he taught us.</title>

print(soup.get_text())

Beautiful Soup: We called him Tortoise because he taught us.
You didn't write that awful page. You're just trying to
get some data out of it. Beautiful Soup is here to 
help. Since 2004, it's been saving programmers hours or
days of work on quick-turnaround screen scraping 
projects.

Eksploracja BeautifulSoup

find_all()

for link in soup.find_all('a'):
    print(link.get('href'))

bs4/download/
#Download
bs4/doc/
#HallOfFame
https://code.launchpad.net/beautifulsoup
https://groups.google.com/forum/?fromgroups#!forum/beautifulsoup
http://www.candlemarkandgleam.com/shop/constellation-games/
http://constellation.crummy.com/Constellation%20Games%20excerpt.html
https://groups.google.com/forum/?fromgroups#!forum/beautifulsoup
https://bugs.launchpad.net/beautifulsoup/
http://lxml.de/
http://code.google.com/p/html5lib/

Czas na ćwiczenia!

Importowanie danych w Pythonie – poziom średniozaawansowany