Python step-by-step: File system operations

Use an example to familiarize yourself with the basic operation of a file: create a file, read a file, modify a file, delete a file, rename a file, determine whether a file exists

1 " "2 Write a table of employee information that can be Queried--school number name age class3 1. Provide a format query interface4 2. Allow users to add or delete employee information5 " "6 ImportOS7Employee_dir ='employee_list'8index=employee_dir+"/index"9 Ten  one if( notos.path.exists (employee_dir)): aOs.mkdir (employee_dir,777) -  - defadd_student (id,name,age,_class): theLocal_file = employee_dir+"/"+Str (id) -     if(os.path.isfile (local_file)): -         Print("id:%s already exists, please add it again"%(ID)) -     Else: +F=open (local_file,"W") -F.write (name+"\ t"+str (age) +"\ t"+_class) + f.close () aF=open (index,"a") atF.write (str (id) +"\ t"+name+"\ n") - f.close () -         Print("id=%s Add Success"%Id) -  - defSelect_student (* *kwargs): -      forKeyinchKwargs.keys (): in         if(key=='ID'): -Local_file = employee_dir+"/"+Str (kwargs[key]) to             if( notos.path.isfile (local_file)): +                 Print("ID does not exist:", Kwargs[key]) -             Else: theF=open (local_file,"R") *                 Print(kwargs[key],f.read ()) $         elif(key=='name'):Panax Notoginseng             if( notos.path.isfile (index)): -                 Print("name does not exist:", Kwargs[key]) the             Else: +I=0 aF=open (index,"R") the                  forLineinchF.readlines (): +Id,name = Line.strip (). Split ("\ t") -                     if(name = =kwargs[key]): $I=i+1 $Select_student (id=Id) -                 if(i==0): -                     Print("name does not exist:", Kwargs[key]) the         Else: -             Print("invalid fetch method, only through ID and name to get!")Wuyi  the  - defmodify_student (id,name,age,_class): wuLocal_file = employee_dir+"/"+Str (id) -     if(os.path.isfile (local_file)): about Os.remove (local_file) $ Rm_line (index,id) - add_student (id,name,age,_class) -         Print("id=%s Modified successfully"%Id) -     Else: a         Print("id:%s does not exist, please add first"%(ID)) +  the defDelete_student (* *kwargs): -      forKeyinchKwargs.keys (): $         if(key=='ID'): theLocal_file = employee_dir+"/"+Str (kwargs[key]) the             if( notos.path.isfile (local_file)): the                 Print("ID does not exist:", kwargs[key],", you cannot delete") the             Else: - Os.remove (local_file) in Rm_line (index,kwargs[key]) the                 Print("Delete id=%s Success"%kwargs[key]) the         elif(key=='name'): about             if( notos.path.isfile (index)): the                 Print("name does not exist:", kwargs[key],", you cannot delete") the             Else: theI=0 +F=open (index,"R") -                  forLineinchF.readlines (): theId,name = Line.strip (). Split ("\ t")Bayi                     if(name = =kwargs[key]): theI=i+1 theDelete_student (id=Id) -                 if(i==0): -                     Print("name does not exist:", kwargs[key],", you cannot delete") the         Else: the             Print("Invalid delete method, only by ID and name to delete!") the  the defRm_line (file,id): -     if( notos.path.isfile (file)): the         Print("file does not exist:", File) the     Else: theF= Open (file,"R")94of = Open (file+". tmp","W") the          forLineinchF.readlines (): theLocalid,localname = Line.strip (). Split ("\ t") the             if(str (id) = =localid):98                 Pass about             Else: - Of.write (line,)101 f.close ()102 of.close ()103         if(os.path.isfile (file+". Tmpt")): Os.remove (file+". Tmpt")104Os.rename (file,file+". Tmpt") theOs.rename (file+". tmp", File)

Python step-by-step: File system operations