python-code-05

Homework Today:
   First, realize the user registration function
      Ideas:
         User input user name, password
         Store user input in a fixed format, such as: egon:123, depositing files
         A new user name and password can be re-registered in a previous file

 whileTRUE:NAME_INP= Input ('Name>>:'). Strip ()#to verify the user name, create the file beforehand.PWD_INP = input ('Password>>:') Chk_pwd_inp= Input ('Password>>:')    ifPWD_INP = =Chk_pwd_inp:with Open ('Db_file', mode=' at', encoding='Utf-8') as F:f.write ('%s:%s\n'%(NAME_INP,PWD_INP))Else:        Print('two times password inconsistency')

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   Second, the realization of user authentication function more:
      Ideas:
         The user enters the account password, reads the account password from the file, compared with the user input

NAME_INP = input ('Username>>:'). Strip () Pwd_inp= Input ('Password>>:') with open ('Db_file', mode='RT', encoding='Utf-8') as F: forLineinchF:line= Line.strip ('\ n') Line= Line.split (':') name=Line[0] pwd= Line[1]        ifNAME_INP = = Name andPWD_INP = =pwd:Print('Validation Successful')             Break    Else:        Print('incorrect user name or password')

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   Third, write the program, realize the file copy function
      Ideas:
         User input source file path and destination file path, execute file copy

 import   sys  if  len (sys.argv)! = 3:  print  ("  USAGE:CP source_file Target_file   " ) Sys.exit () Source_file, Target_file  =sys.argv[1],sys.argv[2]with open (source_file,   " rb  " ) as Read_f, Open (Target_file, " WB   " ) as Write_f:  for  line in   Read_f:write_f.write (line)  

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Tomorrow morning Dictation:
   Looping through files

F=open ('Db_file','RT', encoding='Utf-8') forLineinchF:Print(line) F.close () with open ('Db_file', mode='RT', encoding='Utf-8') as F: forLineinchF:Print(line,end="')

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   Read-only reading of files and notes

With open ('db_file', mode='rt', encoding='  Utf-8') as F:    print(F.read ())1, read only, cannot write 2, when the file does not exist, will error , the file pointer is moved to the beginning of the file when the file exists, and it is at the end of the reading.

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   Write only the way the file is written, and note the precautions

With open ('w', mode='wt', encoding='utf-8 ' As F:    f.write ('w')1, can only write, cannot read 2, An empty file is created when the file does not exist, and the contents of the file are emptied when the file exists

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   Write the file only in the written manner and note the precautions

With open ('w', mode='at', encoding='utf-8 ' As F:    f.write ('\nr')1, can only write, cannot read 2, An empty file is created when the file does not exist, and the pointer is moved to the end of the file when the file exists

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   A brief description of the difference between T and B modes

T mode: Only text files can be used in T mode, and only text files have the concept of character encoding B mode: must not specify the character encoding, only t mode with the character encoding B is a binary mode, is a common file read mode, because all the files in the hard disk are stored in binary form

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Python-code-05