Assignment: regular expression

Assignment: Use regular expressions to complete the following operations

1. Username matching

​ Requirements:
a. The user name can only contain alphanumeric underscores

​ b. Cannot start with a number

​ c. Length is in the range of 6 to 16 bits

from re import fullmatch
user=input('请输入用户名：')
user_name=r'[a-zA-Z_][a-zA-Z_\d]{5,15}'
print(fullmatch(user_name,user))

2. Password match

​ Requirements: 1. Cannot include these special symbols @#¥%^&*

​ 2. Must start with a letter

​ 3. Length is in the range of 6 to 12 digits

from re import fullmatch
password=input('请输入用户名：')
user_password=r'[a-zA-Z][^!@#¥%^&*]{5,11}'
print(fullmatch(user_password,password))

3. IP address matching in ipv4 format
   Tip: The range of IP address is 0.0.0.0-255.255.255.255

user=input('请输入ip地址：')
user_name=r'([1-9]?\d\.){3}\d|(1\d\d\.){3}1\d\d|(2[0-4]\d\.){3}2[0-4]\d|(25[0-5]\.){3}25[0-5]'
print(fullmatch(user_name,user))

4. Extract the value in the user input data (the value includes positive and negative numbers as well as integers and decimals) and sum

例如:“-3.14good87nice19bye” =====> -3.14 + 87 + 19 = 102.86

from re import findall
from functools import reduce
str1='-3.14go-.od87nice19bye'
str2=r'-?\d+\.?\d*'
result=findall(str2,str1)
print(reduce(lambda x,y :x+float(y),result,0))

5. Verify that the input content can only be Chinese characters

   from re import fullmatch
   strs=input('请输入中文：')
   print(fullmatch(r'[\u4e00-\u9fa5]+',strs))
   

6. Match integers or decimals (including positive and negative numbers)

   from re import fullmatch
   strs=input('请输入一个数：')
   print(fullmatch(r'[+-]?(0|[1-9]\d*|0\.\d+|[1-9]\d*\.\d+)',strs))
   

7. Gets a string using a regular expression in all date information to match date date format: 2018-12-6

   Note that the range of year is 1~9999, the range of month is 1~12, and the range of day is 1 _{30 or 1} 31 or 1~29 (leap years are not considered)

   from re import fullmatch
   
   
   str1=r'[1-9]\d{3}-([13578]|1[0-2])-(\d|[1-2]\d|3[01])'
   str2=r'[1-9]\d{3}-([469]|11)-([1-9]|[1-2]\d|30)'
   str3=r'[1-9]\d{3}-2-([1-9]|[1-2]\d)'
   def strs(*args):
       for i in args:
           str4=fullmatch(i,'2018-12-6')
           if str4 !='None':
               return str4
   
   result=strs(str1,str2,str3)
   print(result)