from bs4 import BeautifulSoup 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 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> """ soup = BeautifulSoup(html) #打印一下 soup 对象的内容,格式化输出 print(soup.prettify()) #=================================== #(1)Tag #获取标签内容 #soap+标签 查找的是在所有内容中的第一个符合要求的标签 print(soup.title) #<title>The Dormouse's story</title> print(soup.head) print(soup.a) print(soup.p) #<p class="title" name="dromouse"><b>The Dormouse's story</b></p> #验证对象类型 print(type(soup.a)) ##<class 'bs4.element.Tag'> #把 p 标签的所有属性打印输出了出来 print(soup.p.attrs) # {'class': ['title'], 'name': 'dromouse'} #Tag的name属性 print(soup.name) print(soup.head.name) #[document] #head #单独获取某个属性 print(soup.p['class']) #['title'] print(soup.p.get('class')) #['title'] #更改或新增属性内容 soup.p['class']="newClass" print(soup.p) #<p class="newClass" name="dromouse"><b>The Dormouse's story</b></p> #删除属性 del soup.p['class'] print(soup.p) #<p name="dromouse"><b>The Dormouse's story</b></p> #============================= #(2)NavigableString #获取标签内容 print(soup.p.string) #The Dormouse's story print(soup.a.string) #Elsie #标签内容类型 print(type(soup.p.string)) ##<class 'bs4.element.NavigableString'> #============================= #(3)BeautifulSoup #BeautifulSoup 对象表示的是一个文档的全部内容.大部分时候,可以把它当作 Tag 对象,是一个特殊的 Tag,我们可以分别获取它的类型,名称,以及属性来感受一下 print(type(soup.name)) #<type 'unicode'> print(soup.name) # [document] print(soup.attrs) #{} 空字典 #============================= #(4)Comment #Comment 对象是一个特殊类型的 NavigableString 对象,其实输出的内容仍然不包括注释符号 print(soup.a) #<a class="sister" href="http://example.com/elsie" id="link1"><!-- Elsie --></a> print(soup.a.string) #Elsie print(type(soup.a.string)) #<class 'bs4.element.Comment'>
遍历文档树
from bs4 import BeautifulSoup 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 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> """ soup = BeautifulSoup(html) print("==========================================") #遍历文档树 #(1)直接子节点.contents .children #.contents 和 .children 属性仅包含tag的直接子节点 print(soup.head.contents) #[<title>The Dormouse's story</title>] print(soup.head.contents[0] ) #<title>The Dormouse's story</title> print(soup.head.contents[0].string ) #The Dormouse's story print(soup.head.children) #<listiterator object at 0x7f71457f5710> for child in soup.head.children: print(child) #<title>The Dormouse's story</title> print("=======================1") for child in soup.p.children: print(child) #<b>The Dormouse's story</b> print("=======================2") for child in soup.body.children: print(child) print("==========================================") #(2)所有子孙节点.descendants for child in soup.descendants: print(child) #(3)节点内容:.string 属性 #如果一个标签里面没有标签了,那么 .string 就会返回标签里面的内容。如果标签里面只有唯一的一个标签了,那么 .string 也会返回最里面的内容。 print(soup.head.string) #The Dormouse's story print(soup.title.string) #The Dormouse's story #如果tag包含了多个子节点,tag就无法确定,string 方法应该调用哪个子节点的内容, .string 的输出结果是 None print(soup.html.string) # None #(4)多个内容 .strings .stripped_strings 属性 #for string in soup.strings: # print(repr(string)) #输出的字符串中可能包含了很多空格或空行,使用 .stripped_strings 可以去除多余空白内容 for string in soup.stripped_strings: print(repr(string)) #(5)父节点 .parent 属性 p = soup.p print(p.parent.name) #body print(soup.title.parent.name ) #head #(6)全部父节点 .parents content = soup.head.title.string for parent in content.parents: print(parent.name) #title #head #html #[document] #(7)兄弟节点 #知识点:.next_sibling .previous_sibling 属性 #兄弟节点可以理解为和本节点处在统一级的节点,.next_sibling 属性获取了该节点的下一个兄弟节点,.previous_sibling 则与之相反,如果节点不存在,则返回 None #注意:实际文档中的tag的 .next_sibling 和 .previous_sibling 属性通常是字符串或空白,因为空白或者换行也可以被视作一个节点,所以得到的结果可能是空白或者换行 print soup.p.next_sibling # 实际该处为空白 print soup.p.prev_sibling #None 没有前一个兄弟节点,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" href="http://example.com/elsie" id="link1"><!-- Elsie --></a>, #<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> and #<a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>; #and they lived at the bottom of a well.</p> #(8)全部兄弟节点 #知识点:.next_siblings .previous_siblings 属性 for sibling in soup.a.next_siblings: print(repr(sibling)) #(9)前后节点 #知识点:.next_element .previous_element 属性 #与 .next_sibling .previous_sibling 不同,它并不是针对于兄弟节点,而是在所有节点,不分层次 #<head><title>The Dormouse's story</title></head> #那么它的下一个节点便是 title,它是不分层次关系的 print(soup.head.next_element) #<title>The Dormouse's story</title> #(10)所有前后节点 #知识点:.next_elements .previous_elements 属性 for element in last_a_tag.next_elements: print(repr(element))
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