• 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:
    '
    '
    "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.
        '
    '
    '
    '...'
    '
    '

      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'
    ';
            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:
    "
    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.
        
    ...
    "

      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 = ")).*(?=("))')

  • 相关阅读:
    实验四
    实验一、二
    实验
    网上摘录
    网上摘录(琐碎信息)
    angularJsUIbootstrap系列教程1(使用前的准备)
    angularJS在本机运行时的注意事项
    angularJS在创建指令需要注意的问题(指令中使用ngRepeat)
    angularJsUIbootstrap系列教程2(According)
    ASP.NET Web Forms 4.5的新特性
  • 原文地址:https://www.cnblogs.com/kongzhagen/p/8315204.html
Copyright © 2020-2023  润新知