判断IP地址

# 0-199 200-255
# re_str = r'(1?[0-9]?[0-9]|2[0-5]{2})\.(1?[0-9]?[0-9]|2[0-5]{2})' \
#          r'\.(1?[0-9]?[0-9]|2[0-5]{2})\.(1?[0-9]?[0-9]|2[0-5]{2})'

re_str = r'((1?[0-9]?[0-9]|2[0-5]{2})\.){3}(1?[0-9]?[0-9]|2[0-5]{2})'

result1 = re.fullmatch(re_str, '255.189.10.37')
result2 = re.fullmatch(re_str, '256.189.89.9')
print(result1)
print(result2)

运行结果：
<_sre.SRE_Match object; span=(0, 13), match='255.189.10.37'>
None

计算一个字符串中所有数字的和

re_str = r'\d+\.\d+|\d+'
str1 = 'hello90abc 78sjh12.5'
result1 = re.findall(re_str, str1)
print(result1)
sum1 = 0
for num in result1:
    sum1 += float(num)
print(sum1)

运行结果：
['90', '78', '12.5']
180.5

验证输入的内容只能是汉字

re_str = r'[\u4e00-\u9fff]*'
result1 = re.fullmatch(re_str, '我爱你')
result2 = re.fullmatch(re_str, '我爱你1')
print(result1)
print(result2)

运行结果：
<_sre.SRE_Match object; span=(0, 3), match='我爱你'>
None

验证电话号码

re_str = r'1\d{10}'
result1 = re.fullmatch(re_str, '18323161310')
print(result1)

运行结果：
<_sre.SRE_Match object; span=(0, 11), match='18323161310'>

简单的身份证号码验证

# 没有考虑闰年以及平年时以及每个月对应的天数
re_str = r'[1-8]{2}[0-9]{4}[1-2][8-9][1-9]{2}(0[1-9]|1[0-2])([0-2][1-9]|3[0-1])[0-9]{3}([0-9]|X|x)'
result1 = re.fullmatch(re_str, '13048118970228211x')
print(result1)

运行结果：
<_sre.SRE_Match object; span=(0, 18), match='13048118970228211x'>