re模块介绍

1 re.search()

(匹配，字符串内容)

group() 获取最终匹配结果以字符串输出

groups()以元组()输出 前提是匹配语句用()括起来 匹配分组 输出的时候才有值

groupdict()以字典{}键值对输出 在匹配语句前加 ?P<键名> 前提是在以元组输出的基础上 也就是匹配时用()括起来

import re

result = re.search(r"(?P<ip_address>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})(.*)(?P<content>\[.*\])","10.120.1.1 - - [test is very nice 0800]")
print(result)   #输出匹配的结果 很乱
print(result.group())
print(result.groups())
print(result.groupdict())

<re.Match object; span=(0, 39), match='10.120.1.1 - - [test is very nice 0800]'>
10.120.1.1 - - [test is very nice 0800]
('10.120.1.1', ' - - ', '[test is very nice 0800]')
{'ip_address': '10.120.1.1', 'content': '[test is very nice 0800]'}

Process finished with exit code 0

2 re.match()

(正则匹配，字符串)

只看开头 不会看整个字符串 用的不多

import re

result = re.match(r"p..h","python regex demo")
print(result)

<re.Match object; span=(0, 4), match='pyth'>

Process finished with exit code 0

3 re.findall()

(正则匹配，字符串)

以列表方式返回字符段中所有符合的内容

import re

result = re.findall(r"d..o","python is very demo and that is demo")
print(result)

['demo', 'demo']

Process finished with exit code 0

4 re.split()

(正则匹配，字符串)

正则匹配到的字符 作为 分隔符 分割字符串

import re
data = "root   pts/0    (2023-03-03) 21:00"

rusult = re.split(r"\s{2,}",data)
print(rusult)

['root', 'pts/0', '(2023-03-03) 21:00']

Process finished with exit code 0

5 re.sub()

(正则匹配，替换后的内容，字符串)

正则匹配字符串中的内容 换成 替换后内容

import re

url_list = ["http://1.1.1.1/logo.jpg","http://2.2.2.2/index.php","http://3.3.3.3/index.html"]

ip_address = r"\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}"
#首相把列表中的数据挨个取出来，这是取出来的i值为字符串，才能去执行替换操作
for i in url_list:
    # print(i)
    # print(type(i))
    test = re.sub(ip_address,"www.wuyupeng.com",i)
    print(test)

http://www.wuyupeng.com/logo.jpg
http://www.wuyupeng.com/index.php
http://www.wuyupeng.com/index.html

Process finished with exit code 0

6.re.compile()

将正则表达式编译成对象，通过正则对象调用相应的操作方法完成数据处理

速度快 效率高 处理时间比传统快

import re
import time

start_time = time.time()
list = []
zd = {}
filename = r"E:\projecttest\files\access.log"
data = open(filename,mode="r")
#print(data.read())

#调用re.compile方法把正则语句放里面；变成正则对象
content = r"\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}"
change_content = re.compile(content)

for i in data:
    #ip_addr = re.search(content,i)
    #调用change_content这个正则对象的search搜索i里面的内容
    ip_addr = change_content.search(i)
    list.append(ip_addr.group())
#print(list)
for ip in list:
    if ip not in zd:
        zd[ip] = 1
    else:
        zd[ip] += 1
print(zd)

for i,j in zd.items():
    print("IP%s出现的次数为%s" % (i,j))
stop_time = time.time()

print(stop_time - start_time)

{'124.128.58.67': 38268, '175.6.147.168': 5217, '121.5.79.247': 1739, '194.36.80.225': 1739}
IP124.128.58.67出现的次数为38268
IP175.6.147.168出现的次数为5217
IP121.5.79.247出现的次数为1739
IP194.36.80.225出现的次数为1739
0.0747983455657959

Process finished with exit code 0