Day1 Python Notes

Day1

• Variables and Assignments
  • name = ' Kevin ': If the variable is assigned a STR type requires ' ' cause
  • Age = 21: If an int does not need '
• variable and named
  • Easy to understand: It's best to be able to see the name and know it
  • NUMS_OF_KEVIN_GF = ten
  • NUMSOFKEVINGF = 20: Hump method
  • NAME-OF-KEVIN-GF = 10: Nonstandard naming method, triggering syntax error, Python interprets '-' as ' subtraction '
  • 5name = 2: Number cannot start, na4me (can be used)
  • !name = 4: Special characters cannot resemble [email protected]~&% ...
  • name of To = 5: cannot have spaces between variable names
• Dictionary operation method
  • append (): Append
  • count (): Statistics
  • extend (): Extended
  • index (): Index
  • insert (): Insert
  • pop (): Delete a
  • remove (): Specify delete
  • reverse (): Invert
  • sort (): Sort
• Operator
  • &: with operator
  • |: Or operator
  • ^: also or operator
  • ~: Take the inverse operator
  • <<: Left move operator
  • >>: Right Move operator
• logical operators
  • And: Boolean "and", only true at the same time, returns True
  • Or: Boolean "or", which returns True if one is true
  • Not; Boolean "non", returns False if X is true, or True if X is False
• Member operators
  • In: Returns True if the value returned as found in the specified returns false otherwise
  • Not in: Returns True if no value is found within the specified return, otherwise false
• Identity operator
  • is: Returns True if the Returned property is the same as the specified property, otherwise returns false
  • Not is: Returns True if the returned property is different from the specified property, otherwise returns false
• Nested loops
  • Break: Jump out of this layer of loops
  • Continue: Jump out of this cycle to start the next cycle
• File operations
  • Name_file = open (' xxx ', ' W '): Opens the file The first parameter is the file path + filename, the second argument is open mode
    • W: Write mode
    • R: Read mode
    • A: Append mode
  • Name_file.write (' ssss '): added, must be in writable mode or Append mode
  • Name_file.read (): Read file, must be in readable mode
  • Name_file.readline (): progressive read
  • Name_file.readlines (): Read all Rows
  • Name_file.close (): Close file
• Day1 Job
  • Jobs: Writing Login Interfaces
    • Enter User name password
    • Show welcome message after successful authentication
    • Lock after entering three times

  • 1 ImportSYS2 3locking = ('Login/locking.txt')4Login = ('Login/login.txt')5 6 defMain ():7Count_min =08Count_max = 39 Ten      whileCount_min <Count_max: OneUsername = input ("Please enter user name:")#Guide user to enter user name AWith open (locking,'R') as Locking_file:#open files that record locked users -              forLineinchlocking_file.readlines (): -                 ifUsername = = Line.strip ('\ n'):#determine if the user is in a locked user file theSys.exit ('%s user has been locked ... '%username) -  -Password = input ("Please enter user password:")#Guide user to enter password -With open (login,'R') as Login_file: +              forLineinchlogin_file.readlines (): -USER,PASSWD = Line.strip ('\ n'). Split ()#formats the files that record usernames and passwords and assigns them to user and passwd, respectively +Flog = False#Define a variable A                 ifUsername = = User andPassword = = passwd:#determine if the user name password is correct at                     Print("Landing Success! ") -Flog = True#modifying assigned variables guaranteed to exit the program -                      Break -             ifFlog = =False: -                 ifCount_min < 2: -                     Print("User name password is wrong, please re-enter! ") in                 Else: -Lock (username)#input Error three times the user is added to the lock file toCount_min + = 1 +             Else: -                  Break the  * defLock (username): $With open (locking,'a') as Locking_file:Panax Notoginseng locking_file.write (username) -Locking_file.write ('\ n') the  + if __name__=='__main__': AMain ()

    login.py

Day1 Python Notes