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python爬蟲之BeautifulSoup 使用select方法詳解

更新時間：2017年10月23日 14:38:40 作者：古怪的一陣風

本篇文章主要介紹了python爬蟲之BeautifulSoup 使用select方法詳解，具有一定的參考價值，感興趣的小伙伴們可以參考一下

本文介紹了python爬蟲之BeautifulSoup 使用select方法詳解，分享給大家。具體如下：

<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their names were
<a  rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="sister" id="link1"><!-- Elsie --></a>,
<a  rel="external nofollow" rel="external nofollow" rel="external nofollow" class="sister" id="link2">Lacie</a> and
<a  rel="external nofollow" rel="external nofollow" rel="external nofollow" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
<p class="story">...</p>
"""

我們在寫 CSS 時，標簽名不加任何修飾，類名前加點，id名前加 #，在這里我們也可以利用類似的方法來篩選元素，用到的方法是 soup.select()，返回類型是 list

（1）通過標簽名查找

print soup.select('title') 
#[<title>The Dormouse's story</title>]
 
print soup.select('a')
#[<a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>, <a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>, <a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]
 
print soup.select('b')
#[<b>The Dormouse's story</b>]

（2）通過類名查找

print soup.select('.sister')
#[<a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>, <a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>, <a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]

（3）通過 id 名查找

print soup.select('#link1')
#[<a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>]

（4）組合查找

組合查找即和寫 class 文件時，標簽名與類名、id名進行的組合原理是一樣的，例如查找 p 標簽中，id 等于 link1的內(nèi)容，二者需要用空格分開

print soup.select('p #link1')
#[<a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>]

直接子標簽查找

print soup.select("head > title")
#[<title>The Dormouse's story</title>]

（5）屬性查找

查找時還可以加入屬性元素，屬性需要用中括號括起來，注意屬性和標簽屬于同一節(jié)點，所以中間不能加空格，否則會無法匹配到。

print soup.select("head > title")
#[<title>The Dormouse's story</title>]
 
print soup.select('a[ rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ]')
#[<a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>]

同樣，屬性仍然可以與上述查找方式組合，不在同一節(jié)點的空格隔開，同一節(jié)點的不加空格

print soup.select('p a[ rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ]')
#[<a class="sister"  rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>]

以上就是本文的全部內(nèi)容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

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