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16 `bs object Node name Div. attribute contents ` children descendants get child nodes and descendants

2022-06-28 21:22:00 【Andy Python learning notes】

16 bs object . The node name div. attribute contents children descendants Get child nodes Descendants node

List of articles

1. Association selection

<p> This is blue lantern </p>
<p> But because of the wine left dust </p>
<p> Finally, Zhuang Zhou dreamed of butterfly </p>
<p> You are a gift and a curse </p>

Above HTML The code has 4 individual p node , Our previous node selection method can only select the first one p node .
To choose the first 2、3、4p node , We need to use the association selection method .

Insert picture description here

2. bs object . The node name . attribute contents Get child nodes

contents [kənˈtents]： Content .

Grammar format ：bs object . The node name .contents
Return value ： list
Method of value taking ： list [ Indexes ]

#  Make a statement html_str String variable , Storage part HTML Code 
html_str = """ <html> <head><meta charset="utf-8"><title> Ancient poetry 2 The first </title></head> <body> <div class="poems" id="section1"><h2> Like a dream </h2><h3> Li qingzhao <span>（ The song dynasty ）</span></h3><p> Let's ask the roller shutter </p><p> But the Begonia is still </p><p> To know whether ？ To know whether ？</p><p> It should be green, fat, red and thin </p></div> <div class="poems" id="section2"><h2> Untitled </h2><h3> anonymous </h3> <p> This is blue lantern </p><p> But because of the wine left dust </p><p> Finally, Zhuang Zhou dreamed of butterfly </p><p> You are a gift and a curse </p> </div> </body> </html> """
# 1.  from bs4 Parsing library import BeautifulSoup Class is used to parse data 
from bs4 import BeautifulSoup

# 2.1 BeautifulSoup class （ The string to parse , Parser ）
# 2.2  Pass in 2 Parameters , Instantiate the class to get a BeautifulSoup object  
bs_duixiang = BeautifulSoup(html_str, 'lxml') 

print(" step 1：bs object . The node name div—— For the first 1 individual div node ：")
print(bs_duixiang.div,'\n')

print(" step 2.1：bs object . The node name div. attribute contents—— For the first 1 individual div All children of a node ：")
print(bs_duixiang.div.contents,'\n')

print(" step 2.2 ： attribute contents The data type of the obtained child nodes is list ：")
print(type(bs_duixiang.div.contents),'\n')

print(" step 3： Use list [ Indexes ]—— Value :",'\n')
print("div Node No 1 Child node ：",bs_duixiang.div.contents[0],'\n')
print("div Node No 2 Child node ：",bs_duixiang.div.contents[1],'\n')
print("div Node No 5 Child node ：",bs_duixiang.div.contents[4],'\n')
print("div Node No 5 Text content of child nodes ：",bs_duixiang.div.contents[4].string,'\n')

【 Terminal output 】

 step 1：bs object . The node name div—— For the first 1 individual div node ：
<div class="poems" id="section1"><h2> Like a dream </h2><h3> Li qingzhao <span>（ The song dynasty ）</span></h3><p> Let's ask the roller shutter </p><p> But the Begonia is still </p><p> To know whether ？ To know whether ？</p><p> It should be green, fat, red and thin </p></div> 

 step 2.1：bs object . The node name div. attribute contents—— For the first 1 individual div All children of a node ：
[<h2> Like a dream </h2>, <h3> Li qingzhao <span>（ The song dynasty ）</span></h3>, <p> Let's ask the roller shutter </p>, <p> But the Begonia is still </p>, <p> To know whether ？ To know whether ？</p>, <p> It should be green, fat, red and thin </p>] 

 step 2.2 ： attribute contents The data type of the obtained child nodes is list ：
<class 'list'> 

 step 3： Use list [ Indexes ]—— Value : 

div Node No 1 Child node ： <h2> Like a dream </h2> 

div Node No 2 Child node ： <h3> Li qingzhao <span>（ The song dynasty ）</span></h3> 

div Node No 5 Child node ： <p> To know whether ？ To know whether ？</p> 

div Node No 5 Text content of child nodes ：  To know whether ？ To know whether ？

3. bs object . The node name .children Get child nodes

children[ˈtʃɪldrən]： The children .

Grammar format ：bs object . The node name .children
Return value ： List iterator .
Method of value taking ： use for Loop takes values from the list iterator .
for i,child in enumerate(bs object . The node name .children)

#  Make a statement html_str String variable , Storage part HTML Code 
html_str = """ <html> <head><meta charset="utf-8"><title> Ancient poetry 2 The first </title></head> <body> <div class="poems" id="section1"><h2> Like a dream </h2><h3> Li qingzhao <span>（ The song dynasty ）</span></h3><p> Let's ask the roller shutter </p><p> But the Begonia is still </p><p> To know whether ？ To know whether ？</p><p> It should be green, fat, red and thin </p></div> <div class="poems" id="section2"><h2> Untitled </h2><h3> anonymous </h3> <p> This is blue lantern </p><p> But because of the wine left dust </p><p> Finally, Zhuang Zhou dreamed of butterfly </p><p> You are a gift and a curse </p> </div> </body> </html> """
# 1.  from bs4 Parsing library import BeautifulSoup Class is used to parse data 
from bs4 import BeautifulSoup

# 2.1 BeautifulSoup class （ The string to parse , Parser ）
# 2.2  Pass in 2 Parameters , Instantiate the class to get a BeautifulSoup object  
bs_duixiang = BeautifulSoup(html_str, 'lxml') 

print(" step 1：bs object . The node name div—— For the first 1 individual div node ：")
print(bs_duixiang.div,'\n')

print(" step 2.1：bs object . The node name div. attribute children—— For the first 1 individual div All children of a node ：")
print(bs_duixiang.div.children,'\n')

print(" step 2.2 ： attribute children The data type of the resulting child node is list iterator ：")
print(type(bs_duixiang.div.children),'\n')

print(" step 3.1： use for Loop takes values from the list iterator :")
for i,child in enumerate(bs_duixiang.div.children) :
    print(i, child)

# '\n' The function of is to output a blank line , The purpose is to make the output content beautiful , Convenient view 
print('\n')

print(" step 3.2  From the list iterator child The data type of is tag object ：")
print(type(child),'\n')

print(" step 4： Output No 1 individual div The text content of the last child node of the node :")
print(child.string,'\n')

【 Terminal output 】

 step 1：bs object . The node name div—— For the first 1 individual div node ：
<div class="poems" id="section1"><h2> Like a dream </h2><h3> Li qingzhao <span>（ The song dynasty ）</span></h3><p> Let's ask the roller shutter </p><p> But the Begonia is still </p><p> To know whether ？ To know whether ？</p><p> It should be green, fat, red and thin </p></div> 

 step 2.1：bs object . The node name div. attribute children—— For the first 1 individual div All children of a node ：
<list_iterator object at 0x0000012FAE97B160> 

 step 2.2 ： attribute children The data type of the resulting child node is list iterator ：
<class 'list_iterator'> 

 step 3.1： use for Loop takes values from the list iterator :
0 <h2> Like a dream </h2>
1 <h3> Li qingzhao <span>（ The song dynasty ）</span></h3>
2 <p> Let's ask the roller shutter </p>
3 <p> But the Begonia is still </p>
4 <p> To know whether ？ To know whether ？</p>
5 <p> It should be green, fat, red and thin </p>


 step 3.2  From the list iterator child The data type of is tag object ：
<class 'bs4.element.Tag'> 

 step 4： Output No 1 individual div The text content of the last child node of the node :
 It should be green, fat, red and thin

for i,child in enumerate(bs_duixiang.div.children) in enumerate Refer to relevant notes for usage of .

4. bs object . The node name .descendants Get children's node

descendants [dɪˈsendənts]： Progeny .
generator [ˈdʒenəreɪtə]: generator .

Grammar format ：bs object . The node name .descendants
Return value ： generator .
Method of value taking ： use for Loop takes value from generator .
for i,child in enumerate(bs object . The node name .descendants)

#  Make a statement html_str String variable , Storage part HTML Code 
html_str = """ <html> <head><meta charset="utf-8"><title> Ancient poetry 2 The first </title></head> <body> <div class="poems" id="section1"><h2> Like a dream </h2><h3> Li qingzhao <span>（ The song dynasty ）</span></h3><p> Let's ask the roller shutter </p><p> But the Begonia is still </p><p> To know whether ？ To know whether ？</p><p> It should be green, fat, red and thin </p></div> <div class="poems" id="section2"><h2> Untitled </h2><h3> anonymous </h3> <p> This is blue lantern </p><p> But because of the wine left dust </p><p> Finally, Zhuang Zhou dreamed of butterfly </p><p> You are a gift and a curse </p> </div> </body> </html> """
# 1.  from bs4 Parsing library import BeautifulSoup Class is used to parse data 
from bs4 import BeautifulSoup

# 2.1 BeautifulSoup class （ The string to parse , Parser ）
# 2.2  Pass in 2 Parameters , Instantiate the class to get a BeautifulSoup object  
bs_duixiang = BeautifulSoup(html_str, 'lxml') 

print(" step 1：bs object . The node name div—— For the first 1 individual div node ：")
print(bs_duixiang.div,'\n')

print(" step 2.1：bs object . The node name div. attribute descendants— For the first 1 individual div All descendants of node ：")
print(bs_duixiang.div.descendants,'\n')

print(" step 2.2 ： attribute descendants The data type of the resulting descendant node is generator ：")
print(type(bs_duixiang.div.descendants),'\n')

print(" step 3： use for Loop takes value from generator :")
for i, desc in enumerate(bs_duixiang.div.descendants) :
    print(i, desc )

【 Terminal output 】

 step 1：bs object . The node name div—— For the first 1 individual div node ：
<div class="poems" id="section1"><h2> Like a dream </h2><h3> Li qingzhao <span>（ The song dynasty ）</span></h3><p> Let's ask the roller shutter </p><p> But the Begonia is still </p><p> To know whether ？ To know whether ？</p><p> It should be green, fat, red and thin </p></div> 

 step 2.1：bs object . The node name div. attribute descendants— For the first 1 individual div All descendants of node ：
<generator object Tag.descendants at 0x0000012FAE8F0200> 

 step 2.2 ： attribute descendants The data type of the resulting descendant node is generator ：
<class 'generator'> 

 step 3： use for Loop takes value from generator :
0 <h2> Like a dream </h2>
1  Like a dream 
2 <h3> Li qingzhao <span>（ The song dynasty ）</span></h3>
3  Li qingzhao 
4 <span>（ The song dynasty ）</span>
5 （ The song dynasty ）
6 <p> Let's ask the roller shutter </p>
7  Let's ask the roller shutter 
8 <p> But the Begonia is still </p>
9  But the Begonia is still 
10 <p> To know whether ？ To know whether ？</p>
11  To know whether ？ To know whether ？
12 <p> It should be green, fat, red and thin </p>
13  It should be green, fat, red and thin
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