欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识！
您现在的位置是： 首页  >  IT编程

Python常用爬虫代码总结方便查询

程序员文章站 2024-01-07 09:46:52
beautifulsoup解析页面 from bs4 import beautifulsoup soup = beautifulsoup(htmltxt, "l...

beautifulsoup解析页面

from bs4 import beautifulsoup
soup = beautifulsoup(htmltxt, "lxml")
# 三种装载器
soup = beautifulsoup("<a></p>", "html.parser")
### 只有起始标签的会自动补全，只有结束标签的会自动忽略
### 结果为：<a></a>
soup = beautifulsoup("<a></p>", "lxml")
### 结果为：<html><body><a></a></body></html>
soup = beautifulsoup("<a></p>", "html5lib")
### html5lib则出现一般的标签都会自动补全
### 结果为：<html><head></head><body><a><p></p></a></body></html>
# 根据标签名、id、class、属性等查找标签
### 根据class、id、以及属性alog-action的值和标签类别查询
soup.find("a",class_="title",id="t1",attrs={"alog-action": "qb-ask-uname"}))
### 查询标签内某属性的值
pubtime = soup.find("meta",attrs={"itemprop":"datepublished"}).attrs['content']
### 获取所有class为title的标签
for i in soup.find_all(class_="title"):
  print(i.get_text())
### 获取特定数量的class为title的标签
for i in soup.find_all(class_="title",limit = 2):
  print(i.get_text())
### 获取文本内容时可以指定不同标签之间的分隔符，也可以选择是否去掉前后的空白。
soup = beautifulsoup('<p class="title" id="p1"><b> the dormouses story </b></p><p class="title" id="p1"><b>the dormouses story</b></p>', "html5lib")
soup.find(class_="title").get_text("|", strip=true)
#结果为：the dormouses story|the dormouses story
### 获取class为title的p标签的id
soup.find(class_="title").get("id")
### 对class名称正则：
soup.find_all(class_=re.compile("tit"))
### recursive参数，recursive=false时，只find当前标签的第一级子标签的数据
soup = beautifulsoup('<html><head><title>abc','lxml')
soup.html.find_all("title", recursive=false)

unicode编码转中文

content = "\u65f6\u75c7\u5b85"
content = content.encode("utf8","ignore").decode('unicode_escape')

url encode的解码与解码

from urllib import parse
# 编码
x = "中国你好"
y = parse.quote(x)
print(y)
# 解码
x = parse.unquote(y)
print(x)

html转义字符的解码

from html.parser import htmlparser
htmls = "<div><p>"
txt = htmlparser().unescape(htmls)
print(txt)  . # 输出<div><p>

base64的编码与解码

import base64
# 编码
content = "测试转码文本123"
contents_base64 = base64.b64encode(content.encode('utf-8','ignore')).decode("utf-8")
# 解码
contents = base64.b64decode(contents_base64)

过滤emoji表情

 def filter_emoji(desstr,restr=''):
    try:
      co = re.compile(u'[\u00010000-\u0010ffff]')
    except re.error:
      co = re.compile(u'[\ud800-\udbff][\udc00-\udfff]')
    return co.sub(restr, desstr)

完全过滤script和style标签

import requests
from bs4 import beautifulsoup
soup = beautifulsoup(htmls, "lxml")
for script in soup(["script", "style"]):  
  script.extract()
print(soup)

过滤html的标签，但保留标签里的内容

import re
htmls = "<p>abc</p>"
dr = re.compile(r'<[^>]+>',re.s)
htmls2 = dr.sub('',htmls)
print(htmls2)  #abc
正则提取内容（一般处理json）
rollback({
 "response": {
 "code": "0",
 "msg": "success",
 "dext": ""
 },
 "data": {
 "count": 3,
 "page": 1,
 "article_info": [{
  "title": "“小库里”：适应比赛是首要任务 投篮终会找到节奏",
  "url": "http:\/\/sports.qq.com\/a\/20180704\/035378.htm",
  "time": "2018-07-04 16:58:36",
  "column": "nba",
  "img": "",
  "desc": ""
 }, {
  "title": "首钢体育助力国家冰球集训队 中国冰球联赛年底启动",
  "url": "http:\/\/sports.qq.com\/a\/20180704\/034698.htm",
  "time": "2018-07-04 16:34:44",
  "column": "综合体育",
  "img": "",
  "desc": ""
 }...]
 }
})
import re
# 提取这个json中的每条新闻的title、url
# (.*?)为要提取的内容，可以在正则字符串中加入.*？表示中间省略若干字符
reg_str = r'"title":"(.*?)",.*?"url":"(.*?)"'
pattern = re.compile(reg_str,re.dotall)
items = re.findall(pattern,htmls)
for i in items:
  tilte = i[0]
  url = i[1]

时间操作

# 获取当前日期
today = datetime.date.today()
print(today)   #2018-07-05
# 获取当前时间并格式化
time_now = time.strftime("%y-%m-%d %h:%m:%s",time.localtime(time.time()))
print(time_now)   #2018-07-05 14:20:55
# 对时间戳格式化
a = 1502691655
time_a = time.strftime("%y-%m-%d %h:%m:%s", time.localtime(int(a))) 
print(time_a)    #2017-08-14 14:20:55
# 字符串转为datetime类型
str = "2018-07-01 00:00:00"
datetime.datetime.strptime(st, "%y-%m-%d %h:%m:%s")
# 将时间转化为时间戳
time_line = "2018-07-16 10:38:50"
time_tuple = time.strptime(time_line, "%y-%m-%d %h:%m:%s")
time_line2 = int(time.mktime(time_tuple))
# 明天的日期
today = datetime.date.today()
tomorrow = today + datetime.timedelta(days=1)
print(tomorrow)   #2018-07-06
# 三天前的时间
today = datetime.datetime.today()
tomorrow = today + datetime.timedelta(days=-3)
print(tomorrow)   #2018-07-02 13:37:00.107703
# 计算时间差
start = "2018-07-03 00:00:00"
time_now = datetime.datetime.now()
b = datetime.datetime.strptime(start,'%y-%m-%d %h:%m:%s')
minutes = (time_now-b).seconds/60
days = (time_now-b).days
all_minutes = days*24*60+minutes
print(minutes)   #821.7666666666667
print(days)   #2
print(all_minutes)   #3701.7666666666664

数据库操作

import pymysql
conn = pymysql.connect(host='10.0.8.81', port=3306, user='root', passwd='root',db='xxx', charset='utf8')
cur = conn.cursor()
insert_sql = "insert into tbl_name(id,name,age) values(%s,%s,%s)
id = 1
name = "like"
age = 26
data_list = []
data = (id,name,age)
# 单条插入
cur.execute(insert_sql,data)
conn.commit()
# 批量插入
data_list.append(data)
cur.executemany(insert_sql,data_list)
conn.commit()
#特殊字符处理(name中含有特殊字符)
data = (id,pymysql.escape_string(name),age)
#更新
update_sql = "update tbl_name set content = '%s' where id = "+str(id)
cur.execute(update_sql%(pymysql.escape_string(content)))
conn.commit()
#批量更新
update_sql = "update tbl_recieve set content = %s ,title = %s , is_spider = %s where id = %s"
update_data = (contents,title,is_spider,one_new[0])
update_data_list.append(update_data)
if len(update_data_list) > 500:
try:
  cur.executemany(update_sql,update_data_list) 
  conn.commit()

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，谢谢大家对的支持。如果你想了解更多相关内容请查看下面相关链接

上一篇：

下一篇：

推荐阅读