python之正则表达式使用

# -*- coding: utf-8 -*-
"""
Created on Tue Dec 17 19:29:44 2019

@author: xbxia
"""
import random
import re

#按规则生成指定数量的sn号
def save(count):
    
    with open('devSn.txt', 'a+') as fw_t:
        for i in range(0, count):
            devSn = ('hongdian'+"%08d"%(i))
            print(devSn)
            fw_t.write(devSn)
            fw_t.write('
')
            
 
#正则表达式用法
#从起始位置匹配数字
def match_pattern(content,start,end):
    pattern = re.compile(r'd+')
    result_obj = pattern.match(content,start,end)  
    result = result_obj.group()    #取出匹配的内容
    #print(result)
    return result

#找出字符串个数
def findall_pattern(content):
    pattern = re.compile('hongdian')
    result = pattern.findall(content)
    #print(result)
    return len(result)

#指定位置搜索整个字符串,但只返回第一个匹配结果
def search_pattern(content,pos):
    pattern = re.compile('hongdian')
    result = pattern.search(content,pos)
    print(result)
    



            
if __name__ == '__main__':
    #save(100)
    #match_pattern(content,20,22)
    content = 'h88dhonghhhhhongdian000hongdian'
    search_pattern(content,22)