Webbskrapning i Python

Importera data i Python – fortsättningskurs

Hugo Bowne-Anderson

Data Scientist at DataCamp

HTML

Blandning av ostrukturerad och strukturerad data
Strukturerad data:
- Har en fördefinierad datamodell, eller
- Är organiserad på ett definierat sätt
Ostrukturerad data: saknar dessa egenskaper

ch_1_3.008.png

BeautifulSoup

Tolka och extrahera strukturerad data från HTML

ch_1_3.011.png

Gör taggröra läsbar och extrahera information

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)

Prettified Soup

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>

Utforska BeautifulSoup

Många metoder, till exempel:

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.

Utforska 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/

Nu kör vi en övning!

Importera data i Python – fortsättningskurs