Python3-正则表达式~
import re
pattern=(r'\d+')
# pattern=(r'\d')#['1', '2', '3', '4', '5', '6', '7', '8', '9']
s=('hello 12345 6789')
# print(s)#['12345', '6789']
# 举例1：I love China 输出：anihC evol I
str='I love China!'
#方法一
# def reverse_out(str):
# i=len(str)-1
# while i>=0:
# print(str[i])
# i-=1
#方法二 正则
# pattern=(r'.')
# s=(str)
# print(s)#['I', ' ', 'l', 'o', 'v', 'e', ' ', 'C', 'h', 'i', 'n', 'a', '!']
#例二 I love China 输出：I evol anihC
# pattern=(r'\w+!?')#['I', 'love', 'China']
# pattern=(r'.+')#['I love China']
# pattern=(r'(\w+)(!?)')#[('I', ''), ('love', ''), ('China', '!')]
# s=(str)
# print(s)
# for item in s:
# reverse_out(item)
#匹配小数
pattern = (r'\d+\.\d*')
s = ("3.241592653 PI 100 10001.11 3.")
print(s)