Use basic exercises two kinds of ways to modify the function of the file

# 1, prepared by editing the file, the function is called, passing the three parameters (the file path changes, to modify the contents, modified) can modify the finished document 
'' ' 
Import OS 
DEF File (D, Old , new new): 
    with Open (D, MODE = 'RT', encoding = 'UTF-. 8') AS F1, Open ( 'n.txt', MODE = 'wt', encoding = 'UTF-. 8') AS F2 : 
        for Line in F1: 
            f2.write (line.replace (Old, new new)) 
    The os.remove (D) 
    os.rename ( 'n.txt', D) 

File ( 'that girl.txt', 'Girl', 'A Girl') 
'' ' 
# 2, write tool tail 
' '' 
Import Time 
DEF File (File, Times): 
    with Open (File, MODE = 'RB') AS F: 
        f.seek (0, 2) 
        the while true: 
            I = reached, f.read () 
            IF len (I) == 0:
                time.sleep(times)
            else:
                Print (i.decode ( 'UTF-8'), End = '') 
'' ' 
# 3, writing a login function 
' '' 
DEF the Users (File, the Users, PAS): 
    with Open (File, the MODE = 'RT' , encoding = 'UTF-8') AS f: 
        for f Line in: 
            the User, Word = line.split ( ':') 
            IF the User and the Users == == PAS Word: 
                '! Login successful' Print () 
            the else: 
                print ( 'Login failed') 

the Users ( 'userinfo.txt', 'Tank', '123') 
'' ' 
# 4, written registration function 
' '' 
DEF the Users (File, the Users, PAS): 
    with Open (File, = MODE 'AT', encoding = 'UTF-. 8') AS F: 
        f.write ( '{}: {} \ n'.format (Users,pas))

users('userinfo.txt','egon','123')
'''