python爬蟲(chóng)開(kāi)發(fā)之Beautiful Soup模塊從安裝到詳細(xì)使用方法與實(shí)例

更新時(shí)間：2020年03月09日 09:32:51 作者：love666666shen

這篇文章主要介紹了python爬蟲(chóng)開(kāi)發(fā)之Beautiful Soup模塊詳細(xì)使用方法與實(shí)例,需要的朋友可以參考下

python爬蟲(chóng)模塊Beautiful Soup簡(jiǎn)介

簡(jiǎn)單來(lái)說(shuō)，Beautiful Soup是python的一個(gè)庫(kù)，最主要的功能是從網(wǎng)頁(yè)抓取數(shù)據(jù)。官方解釋如下： Beautiful Soup提供一些簡(jiǎn)單的、python式的函數(shù)用來(lái)處理導(dǎo)航、搜索、修改分析樹(shù)等功能。它是一個(gè)工具箱，通過(guò)解析文檔為用戶(hù)提供需要抓取的數(shù)據(jù)，因?yàn)楹?jiǎn)單，所以不需要多少代碼就可以寫(xiě)出一個(gè)完整的應(yīng)用程序。Beautiful Soup自動(dòng)將輸入文檔轉(zhuǎn)換為Unicode編碼，輸出文檔轉(zhuǎn)換為utf-8編碼。你不需要考慮編碼方式，除非文檔沒(méi)有指定一個(gè)編碼方式，這時(shí)，Beautiful Soup就不能自動(dòng)識(shí)別編碼方式了。然后，你僅僅需要說(shuō)明一下原始編碼方式就可以了。Beautiful Soup已成為和lxml、html6lib一樣出色的python解釋器，為用戶(hù)靈活地提供不同的解析策略或強(qiáng)勁的速度。

python爬蟲(chóng)模塊Beautiful Soup安裝

Beautiful Soup 3 目前已經(jīng)停止開(kāi)發(fā)，推薦在現(xiàn)在的項(xiàng)目中使用Beautiful Soup 4，不過(guò)它已經(jīng)被移植到BS4了，也就是說(shuō)導(dǎo)入時(shí)我們需要 import bs4 。所以這里我們用的版本是 Beautiful Soup 4.3.2 (簡(jiǎn)稱(chēng)BS4)，另外據(jù)說(shuō) BS4 對(duì) Python3 的支持不夠好，不過(guò)我用的是 Python2.7.7，如果有小伙伴用的是 Python3 版本，可以考慮下載 BS3 版本。可以利用 pip 或者 easy_install 來(lái)安裝，以下兩種方法均可

easy_install beautifulsoup4

pip install beautifulsoup4

如果想安裝最新的版本，請(qǐng)直接下載安裝包來(lái)手動(dòng)安裝，也是十分方便的方法。下載完成之后解壓，運(yùn)行下面的命令即可完成安裝

sudo python setup.py install

然后需要安裝 lxml

easy_install lxml

pip install lxml

另一個(gè)可供選擇的解析器是純Python實(shí)現(xiàn)的 html5lib , html5lib的解析方式與瀏覽器相同,可以選擇下列方法來(lái)安裝html5lib:

easy_install html5lib

pip install html5lib

Beautiful Soup支持Python標(biāo)準(zhǔn)庫(kù)中的HTML解析器,還支持一些第三方的解析器，如果我們不安裝它，則 Python 會(huì)使用 Python默認(rèn)的解析器，lxml 解析器更加強(qiáng)大，速度更快，推薦安裝。

解析器	使用方法	優(yōu)勢(shì)	劣勢(shì)
Python標(biāo)準(zhǔn)庫(kù)	BeautifulSoup(markup, “html.parser”)	Python的內(nèi)置標(biāo)準(zhǔn)庫(kù) 執(zhí)行速度適中文檔容錯(cuò)能力強(qiáng)	Python 2.7.3 or 3.2.2)前的版本中文檔容錯(cuò)能力差
lxml HTML 解析器	BeautifulSoup(markup, “l(fā)xml”)	速度快文檔容錯(cuò)能力強(qiáng)	需要安裝C語(yǔ)言庫(kù)
lxml XML 解析器	BeautifulSoup(markup, [“l(fā)xml”, “xml”]) BeautifulSoup(markup, “xml”)	速度快唯一支持XML的解析器	需要安裝C語(yǔ)言庫(kù)
html5lib	BeautifulSoup(markup, “html5lib”)	最好的容錯(cuò)性以瀏覽器的方式解析文檔生成HTML5格式的文檔	速度慢

創(chuàng)建Beautiful Soup對(duì)象

首先必須要導(dǎo)入 bs4 庫(kù)

from bs4 import BeautifulSoup

我們創(chuàng)建一個(gè)字符串，后面的例子我們便會(huì)用它來(lái)演示

html = """
<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" 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" 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" 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" rel="external nofollow" rel="external nofollow" 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" 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" 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>
"""

創(chuàng)建 beautifulsoup 對(duì)象

soup = BeautifulSoup(html)

另外，我們還可以用本地 HTML 文件來(lái)創(chuàng)建對(duì)象，例如

soup = BeautifulSoup(open('index.html'))

上面這句代碼便是將本地 index.html 文件打開(kāi)，用它來(lái)創(chuàng)建 soup 對(duì)象。下面我們來(lái)打印一下 soup 對(duì)象的內(nèi)容，格式化輸出

print soup.prettify()

指定編碼：當(dāng)html為其他類(lèi)型編碼（非utf-8和asc ii），比如GB2312的話，則需要指定相應(yīng)的字符編碼，BeautifulSoup才能正確解析。

htmlCharset = "GB2312"
soup = BeautifulSoup(respHtml, fromEncoding=htmlCharset)

#!/usr/bin/python
# -*- coding: UTF-8 -*-
from bs4 import BeautifulSoup
import re
 
#待分析字符串
html_doc = """
<html>
<head>
 <title>The Dormouse's story</title>
</head>
<body>
<p class="title aq">
 <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" 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" 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" 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" rel="external nofollow" rel="external nofollow" 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" 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" 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>
"""
 
# html字符串創(chuàng)建BeautifulSoup對(duì)象
soup = BeautifulSoup(html_doc, 'html.parser', from_encoding='utf-8')
 
#輸出第一個(gè) title 標(biāo)簽
print soup.title
 
#輸出第一個(gè) title 標(biāo)簽的標(biāo)簽名稱(chēng)
print soup.title.name
 
#輸出第一個(gè) title 標(biāo)簽的包含內(nèi)容
print soup.title.string
 
#輸出第一個(gè) title 標(biāo)簽的父標(biāo)簽的標(biāo)簽名稱(chēng)
print soup.title.parent.name
 
#輸出第一個(gè) p 標(biāo)簽
print soup.p
 
#輸出第一個(gè) p 標(biāo)簽的 class 屬性?xún)?nèi)容
print soup.p['class']
 
#輸出第一個(gè) a 標(biāo)簽的 href 屬性?xún)?nèi)容
print soup.a['href']
'''
soup的屬性可以被添加,刪除或修改. 再說(shuō)一次, soup的屬性操作方法與字典一樣
'''
#修改第一個(gè) a 標(biāo)簽的href屬性為 http://www.baidu.com/
soup.a['href'] = 'http://www.baidu.com/'
 
#給第一個(gè) a 標(biāo)簽添加 name 屬性
soup.a['name'] = u'百度'
 
#刪除第一個(gè) a 標(biāo)簽的 class 屬性為
del soup.a['class']
 
##輸出第一個(gè) p 標(biāo)簽的所有子節(jié)點(diǎn)
print soup.p.contents
 
#輸出第一個(gè) a 標(biāo)簽
print soup.a
 
#輸出所有的 a 標(biāo)簽，以列表形式顯示
print soup.find_all('a')
 
#輸出第一個(gè) id 屬性等于 link3 的 a 標(biāo)簽
print soup.find(id="link3")
 
#獲取所有文字內(nèi)容
print(soup.get_text())
 
#輸出第一個(gè) a 標(biāo)簽的所有屬性信息
print soup.a.attrs
 
for link in soup.find_all('a'):
 #獲取 link 的 href 屬性?xún)?nèi)容
 print(link.get('href'))
 
#對(duì)soup.p的子節(jié)點(diǎn)進(jìn)行循環(huán)輸出 
for child in soup.p.children:
 print(child)
 
#正則匹配，名字中帶有b的標(biāo)簽
for tag in soup.find_all(re.compile("b")):
 print(tag.name)

import bs4#導(dǎo)入BeautifulSoup庫(kù) Soup = BeautifulSoup(html)#其中html 可以是字符串，也可以是句柄需要注意的是，BeautifulSoup會(huì)自動(dòng)檢測(cè)傳入文件的編碼格式，然后轉(zhuǎn)化為Unicode格式通過(guò)如上兩句話，BS自動(dòng)把文檔生成為如上圖中的解析樹(shù)。

Beautiful Soup四大對(duì)象種類(lèi)

Beautiful Soup將復(fù)雜HTML文檔轉(zhuǎn)換成一個(gè)復(fù)雜的樹(shù)形結(jié)構(gòu),每個(gè)節(jié)點(diǎn)都是Python對(duì)象,所有對(duì)象可以歸納為4種:

Tag
NavigableString
BeautifulSoup
Comment

（1）Tag

Tag 是什么？通俗點(diǎn)講就是 HTML 中的一個(gè)個(gè)標(biāo)簽，例如

<title>The Dormouse's story</title>
<a class="sister" href="//www.dbjr.com.cn/" id="link1">jb51</a>

上面的 title a 等等 HTML 標(biāo)簽加上里面包括的內(nèi)容就是 Tag，下面我們來(lái)感受一下怎樣用 Beautiful Soup 來(lái)方便地獲取 Tags 下面每一段代碼中注釋部分即為運(yùn)行結(jié)果

print soup.title
#<title>The Dormouse's story</title>

print soup.head
#<head><title>The Dormouse's story</title></head>

print soup.a
#<a class="sister" href="//www.dbjr.com.cn/" id="link1"></a>

print soup.p
#<p class="title" name="dromouse"><b>The Dormouse's story</b></p>

利用 soup加標(biāo)簽名輕松地獲取這些標(biāo)簽的內(nèi)容，是不是感覺(jué)比正則表達(dá)式方便多了？不過(guò)有一點(diǎn)是，它查找的是在所有內(nèi)容中的第一個(gè)符合要求的標(biāo)簽，如果要查詢(xún)所有的標(biāo)簽，我們?cè)诤竺孢M(jìn)行介紹。soup.title 得到的是title標(biāo)簽，soup.p 得到的是文檔中的第一個(gè)p標(biāo)簽，要想得到所有標(biāo)簽，得用find_all函數(shù)。find_all 函數(shù)返回的是一個(gè)序列，可以對(duì)它進(jìn)行循環(huán)，依次得到想到的東西.。我們可以驗(yàn)證一下這些對(duì)象的類(lèi)型

print type(soup.a)
#<class 'bs4.element.Tag'>

對(duì)于 Tag，它有兩個(gè)重要的屬性，是 name 和 attrs

name

print soup.name
print soup.head.name
#[document]
#head

soup 對(duì)象本身比較特殊，它的 name 即為 [document]，對(duì)于其他內(nèi)部標(biāo)簽，輸出的值便為標(biāo)簽本身的名稱(chēng)。 attrs

print soup.p.attrs
#{'class': ['title'], 'name': 'dromouse'}

在這里，我們把 p 標(biāo)簽的所有屬性打印輸出了出來(lái)，得到的類(lèi)型是一個(gè)字典。如果我們想要單獨(dú)獲取某個(gè)屬性，可以這樣，例如我們獲取它的 class 叫什么

print soup.p['class']
#['title']

還可以這樣，利用get方法，傳入屬性的名稱(chēng)，二者是等價(jià)的

print soup.p.get('class')
#['title']

我們可以對(duì)這些屬性和內(nèi)容等等進(jìn)行修改，例如

soup.p['class']="newClass"
print soup.p
#<p class="newClass" name="dromouse"><b>The Dormouse's story</b></p>

還可以對(duì)這個(gè)屬性進(jìn)行刪除，例如

del soup.p['class']
print soup.p
#<p name="dromouse"><b>The Dormouse's story</b></p>

不過(guò)，對(duì)于修改刪除的操作，不是我們的主要用途，在此不做詳細(xì)介紹了，如果有需要，請(qǐng)查看前面提供的官方文檔

head = soup.find('head')
#head = soup.head
#head = soup.contents[0].contents[0]
print head
 
html = soup.contents[0]  # <html> ... </html>
head = html.contents[0]  # <head> ... </head>
body = html.contents[1]  # <body> ... </body>

可以通過(guò)Tag.attrs訪問(wèn)，返回字典結(jié)構(gòu)的屬性。或者Tag.name這樣訪問(wèn)特定屬性值，如果是多值屬性則以列表形式返回。

（2）NavigableString

既然我們已經(jīng)得到了標(biāo)簽的內(nèi)容，那么問(wèn)題來(lái)了，我們要想獲取標(biāo)簽內(nèi)部的文字怎么辦呢？很簡(jiǎn)單，用 .string 即可，例如

print soup.p.string
#The Dormouse's story

這樣我們就輕松獲取到了標(biāo)簽里面的內(nèi)容，想想如果用正則表達(dá)式要多麻煩。它的類(lèi)型是一個(gè) NavigableString，翻譯過(guò)來(lái)叫可以遍歷的字符串，不過(guò)我們最好還是稱(chēng)它英文名字吧。來(lái)檢查一下它的類(lèi)型

print type(soup.p.string)
#<class 'bs4.element.NavigableString'>

（3）BeautifulSoup

BeautifulSoup 對(duì)象表示的是一個(gè)文檔的全部?jī)?nèi)容.大部分時(shí)候,可以把它當(dāng)作 Tag 對(duì)象，是一個(gè)特殊的 Tag，我們可以分別獲取它的類(lèi)型，名稱(chēng)，以及屬性來(lái)感受一下

print type(soup.name)
#<type 'unicode'>
print soup.name
# [document]
print soup.attrs
#{} 空字典

（4）Comment

Comment 對(duì)象是一個(gè)特殊類(lèi)型的 NavigableString 對(duì)象，其實(shí)輸出的內(nèi)容仍然不包括注釋符號(hào)，但是如果不好好處理它，可能會(huì)對(duì)我們的文本處理造成意想不到的麻煩。我們找一個(gè)帶注釋的標(biāo)簽

print soup.a
print soup.a.string
print type(soup.a.string)

運(yùn)行結(jié)果如下

<a class="sister" href="//www.dbjr.com.cn/" id="link1"></a>
Elsie
<class 'bs4.element.Comment'>

a 標(biāo)簽里的內(nèi)容實(shí)際上是注釋?zhuān)侨绻覀兝?.string 來(lái)輸出它的內(nèi)容，我們發(fā)現(xiàn)它已經(jīng)把注釋符號(hào)去掉了，所以這可能會(huì)給我們帶來(lái)不必要的麻煩。另外我們打印輸出下它的類(lèi)型，發(fā)現(xiàn)它是一個(gè) Comment 類(lèi)型，所以，我們?cè)谑褂们白詈米鲆幌屡袛?，判斷代碼如下

if type(soup.a.string)==bs4.element.Comment:
print soup.a.string

上面的代碼中，我們首先判斷了它的類(lèi)型，是否為 Comment 類(lèi)型，然后再進(jìn)行其他操作，如打印輸出。

Beautiful Soup模塊遍歷文檔樹(shù)

（1）直接子節(jié)點(diǎn)

Tag.Tag_child1：直接通過(guò)下標(biāo)名稱(chēng)訪問(wèn)子節(jié)點(diǎn)。 Tag.contents：以列表形式返回所有子節(jié)點(diǎn)。 Tag.children：生成器，可用于循環(huán)訪問(wèn)：for child in Tag.children 要點(diǎn)：.contents .children 屬性 .contents tag 的 .content 屬性可以將tag的子節(jié)點(diǎn)以列表的方式輸出?？梢允褂?[num] 的形式獲得。使用contents向后遍歷樹(shù)，使用parent向前遍歷樹(shù)

print soup.head.contents
#[<title>The Dormouse's story</title>]

輸出方式為列表，我們可以用列表索引來(lái)獲取它的某一個(gè)元素

print soup.head.contents[0]
#<title>The Dormouse's story</title>

.children 它返回的不是一個(gè) list，不過(guò)我們可以通過(guò)遍歷獲取所有子節(jié)點(diǎn)。我們打印輸出 .children 看一下，可以發(fā)現(xiàn)它是一個(gè) list 生成器對(duì)象。可以使用list可以將其轉(zhuǎn)化為列表。當(dāng)然可以使用for 語(yǔ)句遍歷里面的孩子。

print soup.head.children
#<listiterator object at 0x7f71457f5710>

我們?cè)鯓荧@得里面的內(nèi)容呢？很簡(jiǎn)單，遍歷一下就好了，代碼及結(jié)果如下

for child in soup.body.children:
print child

<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 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" 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" 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" 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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a> and
<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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
 
 
<p class="story">...</p>

（2）所有子孫節(jié)點(diǎn)

知識(shí)點(diǎn)：.descendants 屬性 .descendants .contents 和 .children 屬性?xún)H包含tag的直接子節(jié)點(diǎn)，.descendants 屬性可以對(duì)所有tag的子孫節(jié)點(diǎn)進(jìn)行遞歸循環(huán)，和 children類(lèi)似，我們也需要遍歷獲取其中的內(nèi)容。 Tag.descendants：生成器，可用于循環(huán)訪問(wèn)：for des inTag.descendants

for child in soup.descendants:
print child

運(yùn)行結(jié)果如下，可以發(fā)現(xiàn)，所有的節(jié)點(diǎn)都被打印出來(lái)了，先生成最外層的 HTML標(biāo)簽，其次從 head 標(biāo)簽一個(gè)個(gè)剝離，以此類(lèi)推。

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

（3）節(jié)點(diǎn)內(nèi)容

知識(shí)點(diǎn)：.string 屬性 Tag.String：Tag只有一個(gè)String子節(jié)點(diǎn)是，可以這么訪問(wèn)，否則返回None Tag.Strings：生成器，可用于循環(huán)訪問(wèn)：for str in Tag.Strings 如果tag只有一個(gè) NavigableString 類(lèi)型子節(jié)點(diǎn),那么這個(gè)tag可以使用 .string 得到子節(jié)點(diǎn)。如果一個(gè)tag僅有一個(gè)子節(jié)點(diǎn),那么這個(gè)tag也可以使用 .string 方法,輸出結(jié)果與當(dāng)前唯一子節(jié)點(diǎn)的 .string 結(jié)果相同。通俗點(diǎn)說(shuō)就是：如果一個(gè)標(biāo)簽里面沒(méi)有標(biāo)簽了，那么 .string 就會(huì)返回標(biāo)簽里面的內(nèi)容。如果標(biāo)簽里面只有唯一的一個(gè)標(biāo)簽了，那么 .string 也會(huì)返回最里面的內(nèi)容。如果超過(guò)一個(gè)標(biāo)簽的話，那么就會(huì)返回None。例如

print soup.head.string
#The Dormouse's story
print soup.title.string
#The Dormouse's story

如果tag包含了多個(gè)子節(jié)點(diǎn),tag就無(wú)法確定，string 方法應(yīng)該調(diào)用哪個(gè)子節(jié)點(diǎn)的內(nèi)容, .string 的輸出結(jié)果是 None

print soup.html.string
# None

（4）多個(gè)內(nèi)容

知識(shí)點(diǎn)： .strings .stripped_strings 屬性 .strings 獲取多個(gè)內(nèi)容，不過(guò)需要遍歷獲取，比如下面的例子

for string in soup.strings:
 print(repr(string))
 # u"The Dormouse's story"
 # u'\n\n'
 # u"The Dormouse's story"
 # u'\n\n'
 # u'Once upon a time there were three little sisters; and their names were\n'
 # u'Elsie'
 # u',\n'
 # u'Lacie'
 # u' and\n'
 # u'Tillie'
 # u';\nand they lived at the bottom of a well.'
 # u'\n\n'
 # u'...'
 # u'\n'

.stripped_strings 輸出的字符串中可能包含了很多空格或空行,使用 .stripped_strings 可以去除多余空白內(nèi)容

for string in soup.stripped_strings:
 print(repr(string))
 # u"The Dormouse's story"
 # u"The Dormouse's story"
 # u'Once upon a time there were three little sisters; and their names were'
 # u'Elsie'
 # u','
 # u'Lacie'
 # u'and'
 # u'Tillie'
 # u';\nand they lived at the bottom of a well.'
 # u'...'

（5）父節(jié)點(diǎn)

知識(shí)點(diǎn)： .parent 屬性使用parent獲取父節(jié)點(diǎn)。 Tag.parent：父節(jié)點(diǎn) Tag.parents：父到根的所有節(jié)點(diǎn)

body = soup.body html = body.parent # html是body的父親

p = soup.p
print p.parent.name
#body

content = soup.head.title.string
print content.parent.name
#title

（6）全部父節(jié)點(diǎn)

知識(shí)點(diǎn)：.parents 屬性通過(guò)元素的 .parents 屬性可以遞歸得到元素的所有父輩節(jié)點(diǎn)，例如

content = soup.head.title.string
for parent in content.parents:
 print parent.name
 
title
head
html
[document]

（7）兄弟節(jié)點(diǎn)

知識(shí)點(diǎn)：.next_sibling .previous_sibling 屬性
使用nextSibling, previousSibling獲取前后兄弟
Tag.next_sibling
Tag.next_siblings
Tag.previous_sibling
Tag.previous_siblings
兄弟節(jié)點(diǎn)可以理解為和本節(jié)點(diǎn)處在統(tǒng)一級(jí)的節(jié)點(diǎn)，.next_sibling 屬性獲取了該節(jié)點(diǎn)的下一個(gè)兄弟節(jié)點(diǎn)，.previous_sibling 則與之相反，如果節(jié)點(diǎn)不存在，則返回 None。
注意：實(shí)際文檔中的tag的 .next_sibling 和 .previous_sibling 屬性通常是字符串或空白，因?yàn)榭瞻谆蛘邠Q行也可以被視作一個(gè)節(jié)點(diǎn)，所以得到的結(jié)果可能是空白或者換行

print soup.p.next_sibling
#  實(shí)際該處為空白
print soup.p.prev_sibling
#None 沒(méi)有前一個(gè)兄弟節(jié)點(diǎn)，返回 None
print soup.p.next_sibling.next_sibling
#<p class="story">Once upon a time there were three little sisters; and their names were
#<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" 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" 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" 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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a> and
#<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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>;
#and they lived at the bottom of a well.</p>
#下一個(gè)節(jié)點(diǎn)的下一個(gè)兄弟節(jié)點(diǎn)是我們可以看到的節(jié)點(diǎn)

.next方法：只能針對(duì)單一元素進(jìn)行.next，或者說(shuō)是對(duì)contents列表元素的挨個(gè)清點(diǎn)。比如

soup.contents[1]=u'HTML'
soup.contents[2]=u'\n'

則soup.contents[1].next等價(jià)于soup.contents[2]

head = body.previousSibling    # head和body在同一層，是body的前一個(gè)兄弟
p1 = body.contents[0]          # p1, p2都是body的兒子，我們用contents[0]取得p1
p2 = p1.nextSibling            # p2與p1在同一層，是p1的后一個(gè)兄弟, 當(dāng)然body.content[1]也可得到

contents[]的靈活運(yùn)用也可以尋找關(guān)系節(jié)點(diǎn),尋找祖先或者子孫可以采用findParent(s), findNextSibling(s), findPreviousSibling(s)

（8）全部兄弟節(jié)點(diǎn)

知識(shí)點(diǎn)：.next_siblings .previous_siblings 屬性通過(guò) .next_siblings 和 .previous_siblings 屬性可以對(duì)當(dāng)前節(jié)點(diǎn)的兄弟節(jié)點(diǎn)迭代輸出

for sibling in soup.a.next_siblings:
 print(repr(sibling))
 # u',\n'
 # <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" 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="link2">Lacie</a>
 # u' and\n'
 # <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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>
 # u'; and they lived at the bottom of a well.'
 # None

（9）前后節(jié)點(diǎn)

知識(shí)點(diǎn)：.next_element .previous_element 屬性與 .next_sibling .previous_sibling 不同，它并不是針對(duì)于兄弟節(jié)點(diǎn)，而是在所有節(jié)點(diǎn)，不分層次。比如 head 節(jié)點(diǎn)為

<head><title>The Dormouse's story</title></head>

那么它的下一個(gè)節(jié)點(diǎn)便是 title，它是不分層次關(guān)系的

print soup.head.next_element
#<title>The Dormouse's story</title>

（10）所有前后節(jié)點(diǎn)

知識(shí)點(diǎn)：.next_elements .previous_elements 屬性通過(guò) .next_elements 和 .previous_elements 的迭代器就可以向前或向后訪問(wèn)文檔的解析內(nèi)容,就好像文檔正在被解析一樣

for element in last_a_tag.next_elements:
 print(repr(element))
# u'Tillie'
# u';\nand they lived at the bottom of a well.'
# u'\n\n'
# <p class="story">...</p>
# u'...'
# u'\n'
# None

以上是遍歷文檔樹(shù)的基本用法。

搜索文檔樹(shù)

最常用的是find_all()函數(shù) （1）find_all( name , attrs , recursive , text , **kwargs ) find_all() 方法搜索當(dāng)前tag的所有tag子節(jié)點(diǎn),并判斷是否符合過(guò)濾器的條件 1）name 參數(shù) name 參數(shù)可以查找所有名字為 name 的tag,字符串對(duì)象會(huì)被自動(dòng)忽略掉

#第一個(gè)參數(shù)為T(mén)ag的名稱(chēng) 
tag.find_all(‘title') 
#得到”<title>&%^&*</title>”,結(jié)果為一個(gè)列表 
 
第二個(gè)參數(shù)為匹配的屬性
tag.find_all(“title”,class=”sister”) 
#得到如”<title class = “sister”>%^*&</title> 
# 第二個(gè)參數(shù)也可以為字符串，得到字符串匹配的結(jié)果
tag.find_all(“title”,”sister”) 
#得到如”<title class = “sister”>%^*&</title>

A.傳字符串最簡(jiǎn)單的過(guò)濾器是字符串.在搜索方法中傳入一個(gè)字符串參數(shù),Beautiful Soup會(huì)查找與字符串完整匹配的內(nèi)容,下面的例子用于查找文檔中所有的<b>標(biāo)簽

soup.find_all('b')
# [<b>The Dormouse's story</b>]
 
print soup.find_all('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" 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" 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" 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" rel="external nofollow" rel="external nofollow" 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" 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" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]

B.傳正則表達(dá)式如果傳入正則表達(dá)式作為參數(shù),Beautiful Soup會(huì)通過(guò)正則表達(dá)式的 match() 來(lái)匹配內(nèi)容.下面例子中找出所有以b開(kāi)頭的標(biāo)簽,這表示<body>和<b>標(biāo)簽都應(yīng)該被找到

import re
for tag in soup.find_all(re.compile("^b")):
 print(tag.name)
# body
# b

C.傳列表如果傳入列表參數(shù),Beautiful Soup會(huì)將與列表中任一元素匹配的內(nèi)容返回.下面代碼找到文檔中所有<a>標(biāo)簽和<b>標(biāo)簽

soup.find_all(["a", "b"])
# [<b>The Dormouse's story</b>,
# <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" 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" 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" 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" rel="external nofollow" rel="external nofollow" 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" 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" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]

D.傳 True True 可以匹配任何值,下面代碼查找到所有的tag,但是不會(huì)返回字符串節(jié)點(diǎn)

for tag in soup.find_all(True):
 print(tag.name)
# html
# head
# title
# body
# p
# b
# p
# a
# a

E.傳方法如果沒(méi)有合適過(guò)濾器,那么還可以定義一個(gè)方法,方法只接受一個(gè)元素參數(shù) [4] ,如果這個(gè)方法返回 True 表示當(dāng)前元素匹配并且被找到,如果不是則反回 False。下面方法校驗(yàn)了當(dāng)前元素,如果包含 class 屬性卻不包含 id 屬性,那么將返回 True:

def has_class_but_no_id(tag): return tag.has_attr('class') and not tag.has_attr('id')

將這個(gè)方法作為參數(shù)傳入 find_all() 方法,將得到所有<p>標(biāo)簽:

soup.find_all(has_class_but_no_id)
# [<p class="title"><b>The Dormouse's story</b></p>,
# <p class="story">Once upon a time there were...</p>,
# <p class="story">...</p>]

2）keyword 參數(shù) 注意：如果一個(gè)指定名字的參數(shù)不是搜索內(nèi)置的參數(shù)名,搜索時(shí)會(huì)把該參數(shù)當(dāng)作指定名字tag的屬性來(lái)搜索,如果包含一個(gè)名字為 id 的參數(shù),Beautiful Soup會(huì)搜索每個(gè)tag的”id”屬性

soup.find_all(id='link2')
# [<a class="sister" href="
如果傳入 href 參數(shù),Beautiful Soup會(huì)搜索每個(gè)tag的”href”屬性
soup.find_all(href=re.compile("elsie"))
# [<a class="sister" href="
使用多個(gè)指定名字的參數(shù)可以同時(shí)過(guò)濾tag的多個(gè)屬性
soup.find_all(href=re.compile("elsie"), id='link1')
# [<a class="sister" href="
在這里我們想用 class 過(guò)濾，不過(guò) class 是 python 的關(guān)鍵詞，這怎么辦？加個(gè)下劃線就可以
soup.find_all("a", class_="sister")
# [<a class="sister" href=" # <a class="sister" href=" # <a class="sister" href="
有些tag屬性在搜索不能使用,比如HTML5中的 data-* 屬性

data_soup = BeautifulSoup('<div data-foo="value">foo!</div>')
data_soup.find_all(data-foo="value")
# SyntaxError: keyword can't be an expression

但是可以通過(guò) find_all() 方法的 attrs 參數(shù)定義一個(gè)字典參數(shù)來(lái)搜索包含特殊屬性的tag

data_soup.find_all(attrs={"data-foo": "value"})
# [<div data-foo="value">foo!</div>]

3）text 參數(shù) 通過(guò) text 參數(shù)可以搜搜文檔中的字符串內(nèi)容.與 name 參數(shù)的可選值一樣, text 參數(shù)接受字符串 , 正則表達(dá)式 , 列表, True

soup.find_all(text="Elsie") # [u'Elsie'] soup.find_all(text=["Tillie", "Elsie", "Lacie"]) # [u'Elsie', u'Lacie', u'Tillie'] soup.find_all(text=re.compile("Dormouse")) [u"The Dormouse's story", u"The Dormouse's story"]

4）limit 參數(shù) find_all() 方法返回全部的搜索結(jié)構(gòu),如果文檔樹(shù)很大那么搜索會(huì)很慢.如果我們不需要全部結(jié)果,可以使用 limit 參數(shù)限制返回結(jié)果的數(shù)量.效果與SQL中的limit關(guān)鍵字類(lèi)似,當(dāng)搜索到的結(jié)果數(shù)量達(dá)到 limit 的限制時(shí),就停止搜索返回結(jié)果. 文檔樹(shù)中有3個(gè)tag符合搜索條件,但結(jié)果只返回了2個(gè),因?yàn)槲覀兿拗屏朔祷財(cái)?shù)量
soup.find_all("a", limit=2)
# [<a class="sister" href=" # <a class="sister" href="
5）recursive 參數(shù) 調(diào)用tag的 find_all() 方法時(shí),Beautiful Soup會(huì)檢索當(dāng)前tag的所有子孫節(jié)點(diǎn),如果只想搜索tag的直接子節(jié)點(diǎn),可以使用參數(shù) recursive=False 。一段簡(jiǎn)單的文檔:

<html> <head> <title> The Dormouse's story </title> </head> ...

是否使用 recursive 參數(shù)的搜索結(jié)果:

soup.html.find_all("title")
# [<title>The Dormouse's story</title>]

soup.html.find_all("title", recursive=False)
# []

（2）find(name=None, attrs={}, recursive=True, text=None, **kwargs)
它與 find_all() 方法唯一的區(qū)別是 find_all() 方法的返回結(jié)果是值包含一個(gè)元素的列表,而 find() 方法直接返回結(jié)果。

.find('p'),.findAll('p')：find返回的是字符串值，而且是返回從頭查找到的第一個(gè)tag對(duì)。但是如果這第一個(gè)tag對(duì)包括大量的內(nèi)容，父等級(jí)很高，則同時(shí)其內(nèi)部所包含的，此級(jí)標(biāo)簽也全部都find。findAll返回值是個(gè)列表，如果發(fā)現(xiàn)了一個(gè)同名標(biāo)簽內(nèi)含多個(gè)同名標(biāo)簽，則內(nèi)部的標(biāo)簽一并歸于該父標(biāo)簽顯示，列表其他元素也不再體現(xiàn)那些內(nèi)含的同名子標(biāo)簽。即findAll會(huì)返回所有符合要求的結(jié)果，并以list返回。

soup.findAll(οnclick='document.location...')
    soup.findAll(attrs={'style':r'outline:none;'}) #用來(lái)查找屬性中有style='outline:none;的標(biāo)簽體。

tag搜索

find(tagname)                                  # 直接搜索名為tagname的tag 如：find('head')
find(list)                                     # 搜索在list中的tag，如: find(['head', 'body'])
find(dict)                                     # 搜索在dict中的tag，如:find({'head':True, 'body':True})
find(re.compile(''))                           # 搜索符合正則的tag, 如:find(re.compile('^p')) 搜索以p開(kāi)頭的tag
find(lambda)                       # 搜索函數(shù)返回結(jié)果為true的tag, 如:find(lambda name: if len(name) == 1) 搜索長(zhǎng)度為1的tag
find(True)                                     # 搜索所有tag

attrs搜索

find(id='xxx')                                  # 尋找id屬性為xxx的
find(attrs={id=re.compile('xxx'), algin='xxx'}) # 尋找id屬性符合正則且algin屬性為xxx的
find(attrs={id=True, algin=None})               # 尋找有id屬性但是沒(méi)有algin屬性的

resp1 = soup.findAll('a', attrs = {'href': match1})
resp2 = soup.findAll('h1', attrs = {'class': match2})
resp3 = soup.findAll('img', attrs = {'id': match3})

text搜索文字的搜索會(huì)導(dǎo)致其他搜索給的值如：tag, attrs都失效。方法與搜索tag一致

print p1.text
# u'This is paragraphone.'
print p2.text
# u'This is paragraphtwo.'
# 注意：1，每個(gè)tag的text包括了它以及它子孫的text。2，所有text已經(jīng)被自動(dòng)轉(zhuǎn)為unicode，如果需要，可以自行轉(zhuǎn)碼encode(xxx)

recursive和limit屬性

recursive=False表示只搜索直接兒子，否則搜索整個(gè)子樹(shù)，默認(rèn)為T(mén)rue。
當(dāng)使用findAll或者類(lèi)似返回list的方法時(shí)，limit屬性用于限制返回的數(shù)量，
如:findAll('p', limit=2)：返回首先找到的兩個(gè)tag

（3）find_parents() find_parent()

find_all() 和 find() 只搜索當(dāng)前節(jié)點(diǎn)的所有子節(jié)點(diǎn),孫子節(jié)點(diǎn)等. find_parents() 和 find_parent() 用來(lái)搜索當(dāng)前節(jié)點(diǎn)的父輩節(jié)點(diǎn),搜索方法與普通tag的搜索方法相同,搜索文檔搜索文檔包含的內(nèi)容

（4）find_next_siblings() find_next_sibling()

這2個(gè)方法通過(guò) .next_siblings 屬性對(duì)當(dāng) tag 的所有后面解析的兄弟 tag 節(jié)點(diǎn)進(jìn)行迭代, find_next_siblings() 方法返回所有符合條件的后面的兄弟節(jié)點(diǎn),find_next_sibling() 只返回符合條件的后面的第一個(gè)tag節(jié)點(diǎn)

（5）find_previous_siblings() find_previous_sibling()

這2個(gè)方法通過(guò) .previous_siblings 屬性對(duì)當(dāng)前 tag 的前面解析的兄弟 tag 節(jié)點(diǎn)進(jìn)行迭代, find_previous_siblings()方法返回所有符合條件的前面的兄弟節(jié)點(diǎn), find_previous_sibling() 方法返回第一個(gè)符合條件的前面的兄弟節(jié)點(diǎn)

（6）find_all_next() find_next()

這2個(gè)方法通過(guò) .next_elements 屬性對(duì)當(dāng)前 tag 的之后的 tag 和字符串進(jìn)行迭代, find_all_next() 方法返回所有符合條件的節(jié)點(diǎn), find_next() 方法返回第一個(gè)符合條件的節(jié)點(diǎn)

（7）find_all_previous() 和 find_previous()

這2個(gè)方法通過(guò) .previous_elements 屬性對(duì)當(dāng)前節(jié)點(diǎn)前面的 tag 和字符串進(jìn)行迭代, find_all_previous() 方法返回所有符合條件的節(jié)點(diǎn), find_previous()方法返回第一個(gè)符合條件的節(jié)點(diǎn)

注：以上（2）（3）（4）（5）（6）（7）方法參數(shù)用法與 find_all() 完全相同，原理均類(lèi)似，在此不再贅述。

CSS選擇器

在寫(xiě) CSS 時(shí)，標(biāo)簽名不加任何修飾，類(lèi)名前加點(diǎn)，id名前加 # 在這里我們也可以利用類(lèi)似的方法來(lái)篩選元素，用到的方法是 soup.select()，返回類(lèi)型是 list （1）通過(guò)標(biāo)簽名查找

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

print soup.select('a')
#[<a class="sister" href="
print soup.select('b')
#[<b>The Dormouse's story</b>]

（2）通過(guò)類(lèi)名查找
print soup.select('.sister')
#[<a class="sister" href="
（3）通過(guò) id 名查找
print soup.select('#link1')
#[<a class="sister" href="
（4）組合查找組合查找即和寫(xiě) class 文件時(shí)，標(biāo)簽名與類(lèi)名、id名進(jìn)行的組合原理是一樣的，例如：查找 p 標(biāo)簽中，id 等于 link1的內(nèi)容，二者需要用空格分開(kāi)
print soup.select('p #link1')
#[<a class="sister" href="
直接子標(biāo)簽查找

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

（5）屬性查找查找時(shí)還可以加入屬性元素，屬性需要用中括號(hào)括起來(lái)，注意屬性和標(biāo)簽屬于同一節(jié)點(diǎn)，所以中間不能加空格，否則會(huì)無(wú)法匹配到。
print soup.select('a[class="sister"]')
#[<a class="sister" href="
print soup.select('a[href=")
#[<a class="sister" href="
同樣，屬性仍然可以與上述查找方式組合，不在同一節(jié)點(diǎn)的空格隔開(kāi)，同一節(jié)點(diǎn)的不加空格
print soup.select('p a[href=")
#[<a class="sister" href="
以上的 select 方法返回的結(jié)果都是列表形式，可以遍歷形式輸出，然后用 get_text() 方法來(lái)獲取它的內(nèi)容。

soup = BeautifulSoup(html, 'lxml')
print type(soup.select('title'))
print soup.select('title')[0].get_text()

for title in soup.select('title'):
print title.get_text()

這就是另一種與 find_all 方法有異曲同工之妙的查找方法，是不是感覺(jué)很方便？

print soup.find_all("a", class_="sister") print soup.select("p.title") # 通過(guò)屬性進(jìn)行查找 print soup.find_all("a", attrs={"class": "sister"}) # 通過(guò)文本進(jìn)行查找 print soup.find_all(text="Elsie") print soup.find_all(text=["Tillie", "Elsie", "Lacie"]) # 限制結(jié)果個(gè)數(shù) print soup.find_all("a", limit=2)

本文詳細(xì)講解了python爬蟲(chóng)塊Beautiful Soup從安裝到詳細(xì)使用方法與實(shí)例，更多關(guān)于python爬蟲(chóng)塊Beautiful Soup的使用方法請(qǐng)查看下面的相關(guān)鏈接

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