from re import *
1. 写一个正则表达式判断一个字符串是否是ip地址
规则：一个ip地址由4个数字组成，每个数字之间用.连接。每个数字的大小是0-255
255.189.10.37 正确
256.189.89.9 错误
"""
0-9: \d
10-99: [1-9]\d
100-199: 1\d\d
200-249: 2[0-4]\d
250-255: 25[0-5]
"""
num = r'\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5]'
print(fullmatch(num, '256'))
ip = r'((\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.){3}(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])'
print(fullmatch(ip, '256.189.89.9'))
- 计算一个字符串中所有的数字的和
例如：字符串是：‘hello90abc 78sj-23h12.5’ 结果是90+78+12.5 = 180.5
"""
整数: [-+]?\d+
小数: 23.3, 0.34 \d+.\d*
数字: [-+]?\d+.?\d*
"""
all_nums = findall(r'[-+]?\d+\.?\d*', 'hel0.34lo090abc 78sj-23h12.5')
sum1 = 0
for num_str in all_nums:
sum1 += float(num_str)
print(sum1)
"""
整数: [1-9]\d*
小数: 34.89 [1-9]\d*.\d+
0.34 0.\d+
"""
all_nums = findall(r'[+-]?[1-9]\d*\.\d+|[+-]?0\.\d+|[+-]?[1-9]\d*', 'hel00.34lo090abc 78sj-23h12.5')
print(all_nums)
- 验证输入的内容只能是汉字
value = input('请输入汉字字符串:')
if fullmatch(r'[\u4e00-\u9fa5]+', value):
print('输入合法')
else:
print('输入不合法')
# print(fullmatch(r'c:\\rapidminer\\lib\\plugs'))
print(fullmatch(r'\w*\b-\b\w*|\w*', 'back-shja'))
