bs4 select

1. select() 可以選擇 CSS 標籤，例如選擇 img 標籤。

   [dywang@dywmac zzz]$ cat crawler10.py
   #!/usr/bin/env python
   # coding: utf-8
   import bs4
   
   htmlfile = open('node2.html')
   soup = bs4.BeautifulSoup(htmlfile, 'lxml')
   tag = soup.select('img')
   print("tyep: ", type(tag))
   print("tag: ", tag)
   print("tag text: ")
   for i in range(len(tag)):
   	print(tag[i].getText())
   

2. 執行程式，使用 list 串列的 getText() 輸出結果都空白。

   [dywang@dywmac zzz]$ ./crawler10.py
   ('tyep: ', <type 'list'>)
   ('tag: ', [<img align="BOTTOM" alt="next" border="0" height="24" src="next.png" width="37"/>, <img align="BOTTOM" alt="up" border="0" height="24" src="up.png" width="26"/>, <img align="BOTTOM" alt="previous" border="0" height="24" src="prev.png" width="63"/>, <img align="BOTTOM" alt="contents" border="0" height="24" src="contents.png" width="65"/>])
   tag text: 
   (”, 0)
   (”, 1)
   (”, 2)
   (”, 3)
   

3. 程式最後一行改成列出 list 串列的 index 才有輸出。

   	print(str(tag[i]))
   
   [dywang@dywmac zzz]$ ./crawler10.py
   ('tyep: ', <type 'list'>)
   ('tag: ', [<img align="BOTTOM" alt="next" border="0" height="24" src="next.png" width="37"/>, <img align="BOTTOM" alt="up" border="0" height="24" src="up.png" width="26"/>, <img align="BOTTOM" alt="previous" border="0" height="24" src="prev.png" width="63"/>, <img align="BOTTOM" alt="contents" border="0" height="24" src="contents.png" width="65"/>])
   tag text: 
   ('<img align="BOTTOM" alt="next" border="0" height="24" src="next.png" width="37"/>', 0)
   ('<img align="BOTTOM" alt="up" border="0" height="24" src="up.png" width="26"/>', 1)
   ('<img align="BOTTOM" alt="previous" border="0" height="24" src="prev.png" width="63"/>', 2)
   ('<img align="BOTTOM" alt="contents" border="0" height="24" src="contents.png" width="65"/>', 3)
   

4. 程式最後一行改成列出 list 串列的 get('src') 可以找到所有圖檔。

   	print(tag[i].get('src'))
   
   [dywang@dywmac zzz]$ ./crawler10.py('tyep: ', <type 'list'>)
   ('tag: ', [<img align="BOTTOM" alt="next" border="0" height="24" src="next.png" width="37"/>, <img align="BOTTOM" alt="up" border="0" height="24" src="up.png" width="26"/>, <img align="BOTTOM" alt="previous" border="0" height="24" src="prev.png" width="63"/>, <img align="BOTTOM" alt="contents" border="0" height="24" src="contents.png" width="65"/>])
   tag text: 
   next.png
   up.png
   prev.png
   contents.png