一、 BeautifulSoup搜索文档
1、 使用find_all方法获取指定节点元素的列表对象
taglist=bs.find_all(‘元素名称’)

示例如下:
from bs4 import BeautifulSoup
import urllib.request

def getUrlHtml(strurl):
headers = {
‘User-Agent’: ‘Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36’
}
request=urllib.request.Request(strurl,headers=headers)
html=urllib.request.urlopen(request)

bs=BeautifulSoup(html,"html.parser")
atags=bs.find_all("a")#获取页面所有的a标签
print(type(atags))#查看atags类型
#print(atags)#查看集合内容
for astr in atags:
    print(astr.text.strip())#获取a标签的文本信息
    print(astr['href'])#获取a标签的href属性值

if name == ‘main’:
getUrlHtml(“http://bbs.tianya.cn/list-free-1.shtml”)

2、 使用属性参数进行查找
Tags=bs.find_all(“标签名称”,attrs={‘属性’:’属性对应的值’,’属性2’:’值2’,…})

示例如下:
from bs4 import BeautifulSoup
import urllib.request
import time
def getUrlHtml(strurl):
headers = {
‘User-Agent’: ‘Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36’
}
request=urllib.request.Request(strurl,headers=headers)
html=urllib.request.urlopen(request)

bs=BeautifulSoup(html,"html.parser")
atags=bs.find_all("tr",attrs={'class':'bg'})#根据标签的属性获取标签的集合对象
#print(atags)#查看集合内容
for trtag in atags:
    #print(type(trtag))#查看astr的类型
    print(trtag.text.strip())
    tr_a=trtag.find("a")
    titl_url = tr_a['href']
    #print(type(titl_url))
    #print(titl_url[0:4])#截取从0到4位置的字符串
    if titl_url[0:4]=='http' :
        titlt_full_url=titl_url

    else:
        titlt_full_url="http://bbs.tianya.cn"+titl_url

    print("标题链接地址:",titlt_full_url)
    ######################获取内容信息###########################################
    titlfullurl_index=titlt_full_url.find("do")
    print(titlfullurl_index)
    if titlfullurl_index==-1 :
        request=urllib.request.Request(titlt_full_url,headers=headers)

        html1=urllib.request.urlopen(request)

        bs=BeautifulSoup(html1)

        contenttage=bs.find("div",attrs={'class':'bbs-content clearfix'})#bbs-content clearfix
        print(contenttage.text.strip())
        time.sleep(4)
    else:
        print("不能抓取！")

    ####################################################################################
    print("======================================================================")

if name == ‘main’:
getUrlHtml(“http://bbs.tianya.cn/list-free-1.shtml”)