2017-07-18 50 views
0

我試圖在聯機書籤服務上從我的帳戶中抓取數據。帶有書籤的頁面組織如下:Python網絡抓取:使用多個標籤提取一個屬性

<!DOCTYPE html> 
<html lang="en"> 
<body> 
<div id="item1" class="outer_block"> 
    <div class="title">Bookmark 1</div> 
    <div class="link"> 
     <a href="https://bookmark1.com">https://bookmark1.com</a> 
    </div> 
    <div class="tags"> 
     <a href="http://mylink.com/tag1">tag1</a> 
     <a href="http://mylink.com/tag2">tag2</a> 
    </div> 
</div> 
<div id="item2" class="outer_block"> 
    <div class="title">Bookmark 2</div> 
    <div class="link"> 
     <a href="https://bookmark2.com">https://bookmark2.com</a> 
    </div> 
    <div class="tags"> 
     <a href="http://mylink.com/tag1">tag1</a> 
    </div> 
</div> 
<div id="item3" class="outer_block"> 
    <div class="title">Bookmark 3</div> 
    <div class="link"> 
     <a href="https://bookmark3.com">https://bookmark3.com</a> 
    </div> 
    <div class="tags"> 
     <a href="http://mylink.com/tag3">tag3</a> 
    </div> 
</div> 
</body> 
</html> 

對於每個塊我想提取標題,鏈接和標籤。 在Python 3.5,我做的:

# Import modules 
import requests 
from lxml import html 

# Read the html 
# url = 'mylink' 
# page = requests.get(url) 
# tree = html.fromstring(page.content) 
# This is the replicable example 
tree = html.fromstring('<!DOCTYPE html><html lang="en"><body><div id="item1" class="outer_block"> <div class="title">Item 1</div> <div class="link"> <a href="https://bookmark1.com">https://bookmark1.com</a> </div> <div class="tags"> <a href="http://mylink.com/tag1">tag1</a> <a href="http://mylink.com/tag2">tag2</a> </div></div><div id="item2" class="outer_block"> <div class="title">Item 2</div> <div class="link"> <a href="https://bookmark2.com">https://bookmark2.com</a> </div> <div class="tags"> <a href="http://mylink.com/tag1">tag1</a> </div></div><div id="item3" class="outer_block"> <div class="title">Item 3</div> <div class="link"> <a href="https://bookmark3.com">https://bookmark3.com</a> </div> <div class="tags"> <a href="http://mylink.com/tag3">tag3</a> </div></div></body></html>') 

我使用xpath提取字符串的圖案,說標題:

titles = tree.xpath('//div[@class="title"]/text()') 
print(titles) 

[ '書籤1', '書籤2', '書籤3' ]

爲了提取標籤,我使用相同的原理:

tags = tree.xpath('//div[@class="tags"]//a/text()') 
print(tags) 

[」 tag1','tag2','tag1','tag3']

問題是每個鏈接都有各種標籤,所以我不能將數組titles與數組tags關聯。 我以爲我可以提取每個塊,然後對他們的獨立工作:

blocks = tree.xpath('//div[@class="outer_block"]') 
block1 = blocks[0] 

我不明白的是,當我從block1提取標籤,它仍然保持所有原始的HTML的標籤。

tags_block1 = block1.xpath('//div[@class="tags"]//a/text()' 
print(tags_block1) 

[「TAG1」,「標籤2」,「標籤1」,「標籤3」]

我如何提取標題及相應的標籤,什麼是最好的輸出格式,並沒有任何其他可以更輕鬆地完成這項工作的軟件包?

回答

1

你應該考慮使用BeautifulSoup。考慮下面的代碼(源是HTML字符串):

from bs4 import BeautifulSoup 

soup = BeautifulSoup(source, "html.parser") 
outer_blocks = soup.find_all("div", class_="outer_block") 

for block in outer_blocks: 
    title = block.find("div", class_="title").contents[0] 
    link = block.find("a").contents[0] 
    tags = [x.contents[0] for x in block.find("div", class_="tags").find_all("a")] 
    print([title, link, tags]) 

的輸出是:

['Bookmark 1', 'https://bookmark1.com', ['tag1', 'tag2']] 
['Bookmark 2', 'https://bookmark2.com', ['tag1']] 
['Bookmark 3', 'https://bookmark3.com', ['tag3']]