beautifulSoup基本用法及find选择器

　　总结来源于官方文档：https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#find-all

示例代码段

html_doc = """
<html>
    <head><title>The Dormouse's story <!--Hey, buddy. Want to buy a used parser?-->
    <a><!--Hey, buddy. Want to buy a used parser?--></a></title>
    </head>
<body>
    <p class="title">
        <b>The Dormouse's story</b>
        <a><!--Hey, buddy. Want to buy a used parser?--></a>
    </p>
    <p class="story">Once upon a time there were three little sisters; and their names were
        <a href="http://example.com/elsie" class="sister" id="link1 link4">Elsie</a>,
        <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
        <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
        and they lived at the bottom of a well.
    </p>
    <p class="story">...</p>
"""

　　1、快速操作：

soup.title  == soup.find('title')
# <title>The Dormouse's story</title>

soup.title.name
# u'title'

soup.title.string  == soup.title.text  == soup.title.get_text()
# u'The Dormouse's story'

soup.title.parent.name
# u'head'

soup.p   == soup.find('p')  # . 点属性，只能获取当前标签下的第一个标签
# <p class="title"><b>The Dormouse's story</b></p>

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

soup.a  == soup.find('a')
# <a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>

soup.find_all('a')
# [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,
#  <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,
#  <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

soup.find_all(['a','b'])  # 查找所有的a标签和b标签
soup.find_all(id=["link1","link2"])  # 查找所有id=link1 和id=link2的标签

soup.find(id="link3")
# <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>

　　2、Beautiful Soup对象有四种类型：

　　　　1、BeautifulSoup

　　　　2、tag：标签

　　　　3、NavigableString : 标签中的文本，可包含注释内容

　　　　4、Comment ：标签中的注释，纯注释，没有正文内容

　　标签属性的操做跟字典是一样一样的

　　html多值属性(xml不适合)：

　　　　意思为一个属性名称，它是多值的，即包含多个属性值，即使属性中只有一个值也返回值为list，

　　　　如：class,rel , rev , accept-charset , headers , accesskey

　　　　其它属性为单值属性，即使属性值中有多个空格隔开的值，也是反回一个字符串

soup.a['class']  #['sister']


id_soup = BeautifulSoup('<p id="my id"></p>')
id_soup.p['id']  #'my id'

　　3、html中tag内容输出：　

　　　　string:输出单一子标签文本内容或注释内容（选其一，标签中包含两种内容则输出为None）

　　　　strings: 返回所有子孙标签的文本内容的生成器（不包含注释）

　　　　stripped_strings:返回所有子孙标签的文本内容的生成器（不包含注释,并且在去掉了strings中的空行和空格）

　　　　text:只输出文本内容，可同时输出多个子标签内容

　　　　get_text():只输出文本内容，可同时输出多个子标签内容

　　string:

markup = "<b><!--Hey, buddy. Want to buy a used parser?--></b>"
soup = BeautifulSoup(markup, 'html.parser')
comm = soup.b.string
print(comm)  # Hey, buddy. Want to buy a used parser?
print(type(comm))  #<class 'bs4.element.Comment'>

　　strings:

head_tag = soup.body
for s in head_tag.strings:
    print(repr(s))

结果：
'\n'
"The Dormouse's story"
'\n'
'Once upon a time there were three little sisters; and their names were\n        '
'Elsie'
',\n        '
'Lacie'
' and\n        '
'Tillie'
';\n        and they lived at the bottom of a well.\n    '
'\n'
'...'
'\n'

　　stripped_strings:

head_tag = soup.body
for s in head_tag.stripped_strings:
    print(repr(s))

结果：
"The Dormouse's story"
'Once upon a time there were three little sisters; and their names were'
'Elsie'
','
'Lacie'
'and'
'Tillie'
';\n        and they lived at the bottom of a well.'
'...'

　　text:

soup = BeautifulSoup(html_doc, 'html.parser')
head_tag = soup.body
print(head_tag.text)

结果：
The Dormouse's story
Once upon a time there were three little sisters; and their names were
        Elsie,
        Lacie and
        Tillie;
        and they lived at the bottom of a well.
    
...

soup = BeautifulSoup(html_doc, 'html.parser')
head_tag = soup.body
print(repr(head_tag.text))

结果：
"\nThe Dormouse's story\nOnce upon a time there were three little sisters; and their names were\n        Elsie,\n        Lacie and\n        Tillie;\n        and they lived at the bottom of a well.\n    \n...\n"

　　4、返回子节点列表：

　　　　.contents: 以列表的方式返回节点下的直接子节点

　　　　.children:以生成器的方式反回节点下的直接子节点

soup = BeautifulSoup(html_doc, 'html.parser')
head_tag = soup.head
print(head_tag)
print(head_tag.contents)
print(head_tag.contents[0])
print(head_tag.contents[0].contents)

for ch in head_tag.children:
    print(ch)

结果：
<head><title>The Dormouse's story</title></head>
[<title>The Dormouse's story</title>]
<title>The Dormouse's story</title>
["The Dormouse's story"]
<title>The Dormouse's story</title>

　　5、返回子孙节点的生成器：

　　　　　.descendants: 以列表的方式返回标签下的子孙节点

for ch in head_tag.descendants:
    print(ch)

结果：
<title>The Dormouse's story</title>
The Dormouse's story

　　6、父标签（parent）：如果是bs4对象，不管本来是标签还是文本都可以找到其父标签，但是文本对象不能找到父标签

soup = BeautifulSoup(html_doc, 'html.parser')
tag_title = soup.b  # b标签
print(tag_title.parent)  # b标签的父标签 p
print(type(tag_title.string))  # b标签中的文本的类型,文本中有注释时结果为None <class 'bs4.element.NavigableString'>
print(tag_title.string.parent)  # b标签中文本的父标签 b
print(type(tag_title.text))  # b 标签中的文本类型为str，无bs4属性找到父标签

　　7、递归父标签（parents）：递归得到元素的所有父辈节点

soup = BeautifulSoup(html_doc, 'html.parser')
link = soup.a
for parent in link.parents:
    print(parent.name)

结果：

p
body
html
[document]

　　8、前后节点查询(不是前后标签哦，文本也是节点之一):previous_sibling,next_sibling

　　9、以生成器的方式迭代返回所有兄弟节点

for sib in soup.a.next_siblings:
    print(sib)
    print("---------")

结果：
-------------
,
        
---------
<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>
---------


---------
<a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>
---------
;
        and they lived at the bottom of a well.
    
---------

　　10、搜索文档树

　　　　过滤器：

　　　　　　1、字符串

　　　　　　2、正则表达式

　　　　　　3、列表

　　　　　　4、True

　　　　　　5、方法

html_doc = """<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their names were</p>
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.

<p class="story">...</p>
</body>
"""
from bs4 import BeautifulSoup
import re
soup = BeautifulSoup(html_doc, 'html.parser')
soup.find_all("a")  # 字符串参数
soup.find_all(re.compile("^b"))  # 正则参数
soup.find_all(re.compile("a"))  # 正则参数
soup.find_all(re.compile("l$"))  # 正则参数
soup.find_all(["a", "b"])  # 标签的列表参数
soup.find_all(True)  # 返回所有标签
def has_class_no_id(tag):
    return tag.has_attr("class") and not tag.has_attr("id")
soup.find_all(has_class_no_id)  # 方法参数

　　11、find选择器：

　　　　语法：

　　　　# find_all( name , attrs , recursive , text , **kwargs )
　　　　#  name :要查找的标签名
　　　　#  attrs: 标签的属性
　　　　#  recursive: 递归
　　　　#  text: 查找文本
　　　　# **kwargs :其它 键值参数

　　特殊情况:
　　　　data-foo="value",因中横杠不识别的原因，只能写成attrs={"data-foo":"value"},

　　　　class="value",因class是关键字，所以要写成class_="value"或attrs={"class":"value"}

from bs4 import BeautifulSoup
import re
html_doc = """
<html><head><title>The Dormouse's story</title></head>

<p class="title"><b>The Dormouse's story</b></p>

<p class="story">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>

<p class="story">...</p>
"""

# find_all( name , attrs , recursive , text , **kwargs )
#  name :要查找的标签名（字符串、正则、方法、True）
#  attrs: 标签的属性
#  recursive: 递归
#  text: 查找文本
# **kwargs :其它 键值参数
soup = BeautifulSoup(html_doc, 'html.parser')
print(soup.find_all('p', 'title')) # p标签且class="title"
soup.find_all('title')  # 以列表形式返回 所有title标签a
soup.find_all(attrs={"class":"sister"})  # 以列表形式返回 所有class属性==sister的标签
soup.find_all(id='link2')  # 返回所有id属性==link2的标签
soup.find_all(href=re.compile("elsie")) # 返回所有href属性包含elsie的标签
soup.find_all(id=True)  # 返回 所有包含id属性的标签
soup.find_all(id="link1", href=re.compile('elsie'))  #  id=link1且href包含elsie

关于class的搜索

soup = BeautifulSoup(html_doc, 'html.parser')
css_soup = BeautifulSoup('<p class="body strikeout"></p>', 'html.parser')
css_soup.find_all("p", class_="body")  # 多值class,指定其中一个即可
css_soup.find_all("p", class_="strikeout")
css_soup.find_all("p", class_="body strikeout")  # 精确匹配
# text 参数可以是字符串，列表、方法、True
soup.find_all("a", text="Elsie")  # text="Elsie"的a标签

　　12、父节点方法：

　　　　find_parents( name , attrs , recursive , text , **kwargs )

　　　　find_parent( name , attrs , recursive , text , **kwargs )

html_doc = """<html>
    <head>
        <title>The Dormouse's story</title>
    </head>
<body>
    <p class="title"><b>The Dormouse's story</b></p>
    <p class="story">Once upon a time there were three little sisters; and their names were</p>
    <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
    <p>
        <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
    </p>
    <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
    and they lived at the bottom of a well.
    <p class="story">...</p>
</body>
"""
from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc, 'html.parser')
a_string = soup.find(text="Lacie")  # 文本为Lacie的节点
type(a_string), a_string  # <class 'bs4.element.NavigableString'> Lacie
a_parent = a_string.find_parent()  # a_string的父节点中的第一个节点
a_parent = a_string.find_parent("p")  # a_string的父节点中的第一个p节点
a_parents = a_string.find_parents()  # a_string的父节点
a_parents = a_string.find_parents("a")  # a_string的父点中所有a节点

　　13、后面的邻居节点：

　　　　find_next_siblings( name , attrs , recursive , text , **kwargs )

　　　　find_next_sibling( name , attrs , recursive , text , **kwargs )

html_doc = """<html><head><title>The Dormouse's story</title></head>
<body>
    <p class="title"><b>The Dormouse's story</b></p>
    <p class="story">Once upon a time there were three little sisters; and their names were</p>
    <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
    <b href="http://example.com/elsie" class="sister" id="link1">Elsie</b>,
    <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
    <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
        and they lived at the bottom of a well.
    <p class="story">...</p>
</body>
"""
from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc, 'html.parser')
first_link = soup.a  # 第一个a标签
a_sibling = first_link.find_next_sibling()  # 后面邻居的第一个
a_sibling = first_link.find_next_sibling("a")  # 后面邻居的第一个a
a_siblings = first_link.find_next_siblings()  # 后面的所有邻居
a_siblings = first_link.find_next_siblings("a")  # 后面邻居的所有a邻居

　　14、前面的邻居节点：

　　　　find_previous_siblings( name , attrs , recursive , text , **kwargs )

　　　　find_previous_sibling( name , attrs , recursive , text , **kwargs )

　　15、后面的节点：

　　　　find_all_next( name , attrs , recursive , text , **kwargs )

　　　　find_next( name , attrs , recursive , text , **kwargs )

html_doc = """<html>
    <head>
        <title>The Dormouse's story</title>
    </head>
<body>
    <p class="title"><b>The Dormouse's story</b></p>
    <p class="story">Once upon a time there were three little sisters; and their names were</p>
    <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
    <p>
        <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
    </p>
    <p>
        <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
    </p>
        and they lived at the bottom of a well.
    <p class="story">...</p>
</body>
"""
from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc, 'html.parser')
a_string = soup.find(text="Lacie")
a_next = a_string.find_next()  # 后面所有子孙标签的第一个
a_next = a_string.find_next('a')  # 后面所有子孙标签的第一个a标签
a_nexts = a_string.find_all_next()  # 后面的所有子孙标签
a_nexts = a_string.find_all_next('a')  # 后面的所有子孙标签中的所有a标签

　　16、前面的节点：

　　　　find_all_previous( name , attrs , recursive , text , **kwargs )

　　　　find_previous( name , attrs , recursive , text , **kwargs )

　　17、解析部分文档：

如果仅仅因为想要查找文档中的<a>标签而将整片文档进行解析,实在是浪费内存和时间.最快的方法是从一开始就把<a>标签以外的东西都忽略掉. SoupStrainer 类可以定义文档的某段内容,这样搜索文档时就不必先解析整篇文档,只会解析在 SoupStrainer 中定义过的文档. 创建一个 SoupStrainer 对象并作为 parse_only 参数给 BeautifulSoup 的构造方法即可。

　　SoupStrainer 类参数：name , attrs , recursive , text , **kwargs

html_doc = """<html>
    <head>
        <title>The Dormouse's story</title>
    </head>
<body>
    <p class="title"><b>The Dormouse's story</b></p>
    <p class="story">Once upon a time there were three little sisters; and their names were
        <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
        <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
        <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
    </p>
        and they lived at the bottom of a well.
    <p class="story">...</p>
</body>
"""
from bs4 import SoupStrainer
a_tags = SoupStrainer('a')  # 所有a标签
id_tags = SoupStrainer(id="link2")  # id=link2的标签
def is_short_string(string):
    return len(string) < 10  # string长度小于10，返回True
short_string = SoupStrainer(text=is_short_string)  # 符合条件的文本

from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc, 'html.parser', parse_only=a_tags).prettify()
soup = BeautifulSoup(html_doc, 'html.parser', parse_only=id_tags).prettify()
soup = BeautifulSoup(html_doc, 'html.parser', parse_only=short_string).prettify()

<div id="cnblogs_post_body" class="blogpost-body"> 　　总结来源于官方文档：https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#find-all 示例代码段<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>html_doc = """ <html> <head><title>The Dormouse's story  <a></a></title> </head> <body> The Dormouse's story <a></a> Once upon a time there were three little sisters; and their names were <a href="http://example.com/elsie" class="sister" id="link1 link4">Elsie</a>, <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>; and they lived at the bottom of a well. ... """</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　1、快速操作：<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>soup.title == soup.find('title')# <title>The Dormouse's story</title>soup.title.name# u'title'
soup.title.string == soup.title.text == soup.title.get_text()# u'The Dormouse's story'soup.title.parent.name# u'head'
soup.p == soup.find('p') # . 点属性，只能获取当前标签下的第一个标签# class="title">The Dormouse's storysoup.p['class']# u'title'
soup.a == soup.find('a')# <a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>
soup.find_all('a')# [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,# <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,# <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>] soup.find_all(['a','b']) # 查找所有的a标签和b标签 soup.find_all(id=["link1","link2"]) # 查找所有id=link1 和id=link2的标签 soup.find(id="link3")# <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a> </pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div>　　2、Beautiful Soup对象有四种类型：　　　　1、BeautifulSoup　　　　2、tag：标签　　　　3、NavigableString  : 标签中的文本，可包含注释内容　　　　4、Comment ：标签中的注释，纯注释，没有正文内容 　　标签属性的操做跟字典是一样一样的　　html多值属性(xml不适合)：　　　　意思为一个属性名称，它是多值的，即包含多个属性值，即使属性中只有一个值也返回值为list，　　　　如：class,<tt class="docutils literal">rel</tt> , <tt class="docutils literal">rev</tt> , <tt class="docutils literal">accept-charset</tt> , <tt class="docutils literal">headers</tt> , <tt class="docutils literal">accesskey</tt>　　　　其它属性为单值属性，即使属性值中有多个空格隔开的值，也是反回一个字符串<div class="cnblogs_code"><pre>soup.a['class'] #['sister']

id_soup = BeautifulSoup('')id_soup.p['id'] #'my id'</pre></div> 　　3、html中tag内容输出：　　　　　string:输出单一子标签文本内容或注释内容（选其一，标签中包含两种内容则输出为None）　　　　strings: 返回所有子孙标签的文本内容的生成器（不包含注释）　　　　stripped_strings:返回所有子孙标签的文本内容的生成器（不包含注释,并且在去掉了strings中的空行和空格）　　　　text:只输出文本内容，可同时输出多个子标签内容　　　　get_text():只输出文本内容，可同时输出多个子标签内容　　string:<div class="cnblogs_code"><pre>markup = ""soup = BeautifulSoup(markup, 'html.parser')comm = soup.b.stringprint(comm) # Hey, buddy. Want to buy a used parser?print(type(comm)) #<class 'bs4.element.Comment'></pre></div> 　　strings:<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>head_tag = soup.bodyfor s in head_tag.strings: print(repr(s))
结果：'\n'"The Dormouse's story"'\n''Once upon a time there were three little sisters; and their names were\n ''Elsie'',\n ''Lacie'' and\n ''Tillie'';\n and they lived at the bottom of a well.\n ''\n''...''\n'</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div>　　stripped_strings:<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>head_tag = soup.bodyfor s in head_tag.stripped_strings: print(repr(s))
结果："The Dormouse's story"'Once upon a time there were three little sisters; and their names were''Elsie'',''Lacie''and''Tillie'';\n and they lived at the bottom of a well.''...'</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div>　　text:<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>soup = BeautifulSoup(html_doc, 'html.parser')head_tag = soup.bodyprint(head_tag.text)
结果：The Dormouse's storyOnce upon a time there were three little sisters; and their names were Elsie, Lacie and Tillie; and they lived at the bottom of a well. ...</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div><div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>soup = BeautifulSoup(html_doc, 'html.parser')head_tag = soup.bodyprint(repr(head_tag.text))
结果："\nThe Dormouse's story\nOnce upon a time there were three little sisters; and their names were\n Elsie,\n Lacie and\n Tillie;\n and they lived at the bottom of a well.\n \n...\n"</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div>  　　4、返回子节点列表：　　　　.contents: 以列表的方式返回节点下的直接子节点　　　　.children:以生成器的方式反回节点下的直接子节点<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>soup = BeautifulSoup(html_doc, 'html.parser')head_tag = soup.headprint(head_tag)print(head_tag.contents)print(head_tag.contents[0])print(head_tag.contents[0].contents)
for ch in head_tag.children: print(ch)
结果：<head><title>The Dormouse's story</title></head>[<title>The Dormouse's story</title>]<title>The Dormouse's story</title>["The Dormouse's story"]<title>The Dormouse's story</title></pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　5、返回子孙节点的生成器：　　　　　.descendants: 以列表的方式返回标签下的子孙节点<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>for ch in head_tag.descendants: print(ch)
结果：<title>The Dormouse's story</title>The Dormouse's story</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　6、父标签（parent）：如果是bs4对象，不管本来是标签还是文本都可以找到其父标签，但是文本对象不能找到父标签<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>soup = BeautifulSoup(html_doc, 'html.parser')tag_title = soup.b # b标签print(tag_title.parent) # b标签的父标签 pprint(type(tag_title.string)) # b标签中的文本的类型,文本中有注释时结果为None <class 'bs4.element.NavigableString'>print(tag_title.string.parent) # b标签中文本的父标签 bprint(type(tag_title.text)) # b 标签中的文本类型为str，无bs4属性找到父标签</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　7、递归父标签（parents）：递归得到元素的所有父辈节点<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>soup = BeautifulSoup(html_doc, 'html.parser')link = soup.afor parent in link.parents: print(parent.name) 结果： </pre>p body html [document]

<div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　8、前后节点查询(不是前后标签哦，文本也是节点之一):previous_sibling,next_sibling<img src="https://images2017.cnblogs.com/blog/931154/201801/931154-20180124082140694-1377077553.png" alt="">  　　9、以生成器的方式迭代返回所有兄弟节点<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>for sib in soup.a.next_siblings: print(sib) print("---------")
结果：-------------, ---------<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>---------

---------<a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>---------; and they lived at the bottom of a well. ---------</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　10、搜索文档树　　　　过滤器：　　　　　　1、字符串　　　　　　2、正则表达式　　　　　　3、列表　　　　　　4、True　　　　　　5、方法<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>html_doc = """<html><head><title>The Dormouse's story</title></head><body>class="title">The Dormouse's storyclass="story">Once upon a time there were three little sisters; and their names were<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;and they lived at the bottom of a well.
class="story">...</body>"""from bs4 import BeautifulSoupimport resoup = BeautifulSoup(html_doc, 'html.parser')soup.find_all("a") # 字符串参数soup.find_all(re.compile("^b")) # 正则参数soup.find_all(re.compile("a")) # 正则参数soup.find_all(re.compile("l$")) # 正则参数soup.find_all(["a", "b"]) # 标签的列表参数soup.find_all(True) # 返回所有标签def has_class_no_id(tag): return tag.has_attr("class") and not tag.has_attr("id")soup.find_all(has_class_no_id) # 方法参数</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　11、find选择器：　　　　语法：<pre>　　　　# find_all( name , attrs , recursive , text , **kwargs )　　　　# name :要查找的标签名　　　　# attrs: 标签的属性　　　　# recursive: 递归　　　　# text: 查找文本　　　　# **kwargs :其它键值参数 　　特殊情况: 　　　　data-foo="value",因中横杠不识别的原因，只能写成attrs={"data-foo":"value"},</pre><pre>　　　　class="value",因class是关键字，所以要写成class_="value"或attrs={"class":"value"}</pre><div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>from bs4 import BeautifulSoupimport rehtml_doc = """<html><head><title>The Dormouse's story</title></head>
class="title">The Dormouse's story
class="story">Once upon a time there were three little sisters; and their names were<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;and they lived at the bottom of a well.
class="story">..."""# find_all( name , attrs , recursive , text , **kwargs )# name :要查找的标签名（字符串、正则、方法、True）# attrs: 标签的属性# recursive: 递归# text: 查找文本# **kwargs :其它键值参数soup = BeautifulSoup(html_doc, 'html.parser')print(soup.find_all('p', 'title')) # p标签且class="title"soup.find_all('title') # 以列表形式返回所有title标签asoup.find_all(attrs={"class":"sister"}) # 以列表形式返回所有class属性==sister的标签soup.find_all(id='link2') # 返回所有id属性==link2的标签soup.find_all(href=re.compile("elsie")) # 返回所有href属性包含elsie的标签soup.find_all(id=True) # 返回所有包含id属性的标签soup.find_all(id="link1", href=re.compile('elsie')) # id=link1且href包含elsie</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div><img src="https://images2017.cnblogs.com/blog/931154/201801/931154-20180128222706647-1457600468.png" alt=""><pre>关于class的搜索</pre><div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>soup = BeautifulSoup(html_doc, 'html.parser')css_soup = BeautifulSoup('', 'html.parser')css_soup.find_all("p", class_="body") # 多值class,指定其中一个即可css_soup.find_all("p", class_="strikeout")css_soup.find_all("p", class_="body strikeout") # 精确匹配# text 参数可以是字符串，列表、方法、Truesoup.find_all("a", text="Elsie") # text="Elsie"的a标签</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　12、父节点方法：　　　　find_parents( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> )　　　　find_parent( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> )<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>html_doc = """<html> <head> <title>The Dormouse's story</title> </head><body> class="title">The Dormouse's story class="story">Once upon a time there were three little sisters; and their names were <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>, <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>; and they lived at the bottom of a well. class="story">...</body>"""from bs4 import BeautifulSoupsoup = BeautifulSoup(html_doc, 'html.parser')a_string = soup.find(text="Lacie") # 文本为Lacie的节点type(a_string), a_string # <class 'bs4.element.NavigableString'> Laciea_parent = a_string.find_parent() # a_string的父节点中的第一个节点a_parent = a_string.find_parent("p") # a_string的父节点中的第一个p节点a_parents = a_string.find_parents() # a_string的父节点a_parents = a_string.find_parents("a") # a_string的父点中所有a节点</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> 　　13、后面的邻居节点：　　　　find_next_siblings( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> )　　　　find_next_sibling( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> )<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>html_doc = """<html><head><title>The Dormouse's story</title></head><body> class="title">The Dormouse's story class="story">Once upon a time there were three little sisters; and their names were <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>, "http://example.com/elsie" class="sister" id="link1">Elsie, <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>; and they lived at the bottom of a well. class="story">...</body>"""from bs4 import BeautifulSoupsoup = BeautifulSoup(html_doc, 'html.parser')first_link = soup.a # 第一个a标签a_sibling = first_link.find_next_sibling() # 后面邻居的第一个a_sibling = first_link.find_next_sibling("a") # 后面邻居的第一个aa_siblings = first_link.find_next_siblings() # 后面的所有邻居a_siblings = first_link.find_next_siblings("a") # 后面邻居的所有a邻居</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div>  　　14、前面的邻居节点：　　　　find_previous_siblings( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> )　　　　find_previous_sibling( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> ) 　　15、后面的节点：　　　　find_all_next( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> )　　　　find_next( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> )<div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>html_doc = """<html> <head> <title>The Dormouse's story</title> </head><body> class="title">The Dormouse's story class="story">Once upon a time there were three little sisters; and their names were <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>, <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>; and they lived at the bottom of a well. class="story">...</body>"""from bs4 import BeautifulSoupsoup = BeautifulSoup(html_doc, 'html.parser')a_string = soup.find(text="Lacie")a_next = a_string.find_next() # 后面所有子孙标签的第一个a_next = a_string.find_next('a') # 后面所有子孙标签的第一个a标签a_nexts = a_string.find_all_next() # 后面的所有子孙标签a_nexts = a_string.find_all_next('a') # 后面的所有子孙标签中的所有a标签</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div>  　　16、前面的节点：　　　　find_all_previous( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> )　　　　find_previous( <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a> ) 　　17、解析部分文档：　　　　如果仅仅因为想要查找文档中的<a>标签而将整片文档进行解析,实在是浪费内存和时间.最快的方法是从一开始就把<a>标签以外的东西都忽略掉. <tt class="docutils literal">SoupStrainer</tt> 类可以定义文档的某段内容,这样搜索文档时就不必先解析整篇文档,只会解析在 <tt class="docutils literal">SoupStrainer</tt> 中定义过的文档. 创建一个 <tt class="docutils literal">SoupStrainer</tt> 对象并作为 <tt class="docutils literal">parse_only</tt> 参数给 <tt class="docutils literal">BeautifulSoup</tt> 的构造方法即可。<tt class="docutils literal">　　SoupStrainer</tt> 类参数：<a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#id32">name</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#css">attrs</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#recursive">recursive</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#text">text</a> , <a class="reference internal" href="https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#keyword">**kwargs</a><div class="cnblogs_code"><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div><pre>html_doc = """<html> <head> <title>The Dormouse's story</title> </head><body> class="title">The Dormouse's story class="story">Once upon a time there were three little sisters; and their names were <a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>, <a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and <a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>; and they lived at the bottom of a well. class="story">...</body>"""from bs4 import SoupStrainera_tags = SoupStrainer('a') # 所有a标签id_tags = SoupStrainer(id="link2") # id=link2的标签def is_short_string(string): return len(string) < 10 # string长度小于10，返回Trueshort_string = SoupStrainer(text=is_short_string) # 符合条件的文本
from bs4 import BeautifulSoupsoup = BeautifulSoup(html_doc, 'html.parser', parse_only=a_tags).prettify()soup = BeautifulSoup(html_doc, 'html.parser', parse_only=id_tags).prettify()soup = BeautifulSoup(html_doc, 'html.parser', parse_only=short_string).prettify()</pre><div class="cnblogs_code_toolbar"><a href="javascript:void(0);" onclick="copyCnblogsCode(this)" title="复制代码"><img src="//common.cnblogs.com/images/copycode.gif" alt="复制代码"></a></div></div> </div>

posted @ 2018-10-07 10:49 月黑风高夜夜欢阅读(7683) 评论(0) 编辑收藏举报

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beautifulSoup基本用法及find选择器

总结来源于官方文档：https://www.crummy.com/software/BeautifulSoup/bs4/doc/index.zh.html#find-all

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