Python实战之正则表达式RE/re学习笔记及简单练习
# .,\w,\s,\d,,^,$
# *,+,?,{n},{n,},{n,m}
# re模块用于对python的正则表达式的操作。
#
# 字符:
#
# . 匹配除换行符以外的任意字符
# \w 匹配字母或数字或下划线或汉字
# \s 匹配任意的空白符
# \d 匹配数字
# \b 匹配单词的开始或结束
# ^ 匹配字符串的开始
# $ 匹配字符串的结束
#
# 次数:
#
# * 重复零次或更多次
# + 重复一次或更多次
# ? 重复零次或一次
# {n} 重复n次
# {n,} 重复n次或更多次
# {n,m} 重复n到m次
import re
# match(pattern, string, flags=0)
# 从起始位置开始根据模型去字符串中匹配指定内容,匹配单个
# 正则表达式
# 要匹配的字符串
# 标志位,用于控制正则表达式的匹配方式
# strings = re.match('\d+','123df45')
# print(strings)
# print(strings.group())
# print(strings.groups())
# <_sre.SRE_Match object; span=(0, 3), match='123'>
# 123
# ()
#根据模型去字符串中匹配指定内容,匹配单个
# obj = re.search('\d+','u9f34k')
# print(obj)
# print(obj.group())
# <_sre.SRE_Match object; span=(1, 2), match='9'>
# 9
# group和groups
# a = '123abc456'
# print(re.search("([0-9]*)([a-z]*)([0-9]*)",a).group())
# # 123abc456
# print(re.search("([0-9]*)([a-z]*)([0-9]*)",a).groups())
# # ('123', 'abc', '456')
# print(re.search("([0-9]*)([a-z]*)([0-9]*)",a).group(0))
# # 123abc456
# print(re.search("([0-9]*)([a-z]*)([0-9]*)",a).group(1))
# # 123
# print(re.search("([0-9]*)([a-z]*)([0-9]*)",a).group(2))
# #abc
# print(re.search("([0-9]*)([a-z]*)([0-9]*)",a).group(3))
# #456
# findall(pattern, string, flags=0)
# 上述两中方式均用于匹配单值,即:只能匹配字符串中的一个,如果想要匹配到字符串中所有符合条件的元素,则需要使用 findall。
# a = '123abc567'
# obj = re.findall('\d+',a)
# print(obj)
# print()
# ['123', '567']
# sub(pattern, repl, string, count=0, flags=0)
# 用于替换匹配的字符串
# content = '123abc456'
# new_content = re.sub('\d+','sb',content)
# # sbabcsb
# print(new_content)
# new = re.sub('\d+','xxoo',content,3)
# print(new)
# xxooabcxxoo
content = "'1 - 2 * ((60-30+1*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2) )'"
# new_content = re.split('\*',content)
# print(new_content)
# # ["'1 - 2 ", ' ((60-30+1', '(9-2', '5/3+7/3', '99/4', '2998+10', '568/14))-(-4', '3)/(16-3', "2) )'"]
# new_content2 = re.split('\*',content,1)
# print(new_content2)
# # ["'1 - 2 ", " ((60-30+1*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2) )'"]
#
# new_content3 = re.split('\*',content,3)
# print(new_content3)
# # ["'1 - 2 ", ' ((60-30+1', '(9-2', "5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2) )'"]
# new_content = re.split('[\+\-\*\/]+',content)
# print(new_content)
# ["'1 ", ' 2 ', ' ((60', '30', '1', '(9', '2', '5', '3', '7', '3', '99', '4', '2998', '10', '568', '14))', '(', '4', '3)', '(16', '3', "2) )'"]
# inpp = '1-2*((60-30 +(-40-5)*(9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2))'
# inpp = re.sub('\s*','',inpp)
# print(inpp)
# # 1-2*((60-30+(-40-5)*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))
#
# new_content = re.split('\(([\+\-\*\/]?\d+[\+\-\*\/]?\d+){1}\)',inpp, 1)
# print(new_content)
posted on 2017-07-05 21:23 William126 阅读(1231) 评论(0) 编辑 收藏 举报