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()

最后一个方法：

patel = re.compile(\'(?<=(original_tel = “)).*(?=(“))\’)

本文链接：https://www.cnblogs.com/kongzhagen/p/8315204.html

beautifulSoup基本用法及find选择器 - 孔扎根

beautifulSoup基本用法及find选择器

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