class Student:  stuID = ""  name = ""  sex = "M"  classID = "NULL"    #set ID  def setStuID(self,stuID):   self.stuID = stuID    def setName(self,name):   self.name = name    def setSex(self,sex):   self.sex = sex     def setClassID(self,classID):   self.classID = classID    def getStuId(self):   return self.stuID    def getName(self):   return self.name    def getSex(self):   return self.sex    def getClassID(self):   return self.classID 

import os import re import sys import string import student  #save file global FILEPATH FILEPATH = "student.db" #temporary file global TEMPFILE TEMPFILE = "temp.db"  #This is menu def menu():  while True :   print "1.Add a student information"   print "2.Query student information"   print "3.Delete a student information"   print "0.Quit"   opt = raw_input("Select:")   if opt == "1":    while True:     addStudent()     opt2 = raw_input("Continue Add(Y/N)?:")     if opt2 == "Y" or opt2 == "y" or opt2 == "":      continue     else:      break   elif opt == "2":    while True:     query()     opt2 = raw_input("Continue Query(Y/N)?:")     if opt2 == "Y" or opt2 == "y" or opt2 == "":      continue     else:      break      elif opt == "3":    while True:     delMenu()     opt2 = raw_input("Continue Delete(Y/N)?:")     if opt2 == "Y" or opt2 == "y" or opt2 == "":      continue     else:      break      elif opt == "0" :    exitProgram()     break   else:    print "Error input"      #Add a student def addStudent() :  stu = student.Student()  while True:   stuID = raw_input("ID(001-999):")   #match ID 001-999   p = re.match("^[0-9]{3}$", stuID)   if p :    if stuID == "000":     print "ID must be 001-999"     continue    if isIDExist(stuID):     print "ID = %s already exist!" % stuID     continue    else :      stu.setStuID(stuID)    break   else:    print "ID must be 001-999"    while True:     stuName = raw_input("Name(a-z,A-Z,5 char):")   #match name a-z A-Z 5 char   p = re.match("^[a-zA-Z]{1,5}$",stuName)   if p :    stu.setName(stuName)    break   else :    print "Name format error must a-z,A-Z,within 5 char"    while True:    stuSex = raw_input("Sex(default is M):")   #default value   if stuSex == "":    stu.setSex("M")    print "Sex:M"    break   if stuSex =="M" or stuSex == "m":    stu.setSex(string.upper(stuSex))    break      #if stuSex == "M" or stuSex == "m" || stuSex == "F" stuSex == "f":   p = re.match("^M|m|F|f$",stuSex)   if p :    stu.setSex(string.upper(stuSex))    break   else :    print "Sex(M/f)"     while True:   stuClass = raw_input("Class(01-99):")   #default value   if stuClass == "":    stu.setClassID("NULL")    print "CLASS:NULL"    break   #match 00-99   p = re.match("^[0-9]{2}$",stuClass)   if p :    #get rid of 00    if stuClass == "00":     print "Class must 01-99"     continue    stu.setClassID(stuClass)    break   else:    print "Class must 01-99"  #save to file    file1 = open(FILEPATH,"a")  print "ID/tNAME/tSEX/tCLASS"  print stu.getStuId(),"/t",stu.getName(),"/t",stu.getSex(),"/t",stu.getClassID()  file1.write(stu.getStuId()+"/t"+stu.getName()+"/t"+stu.getSex()+"/t"+stu.getClassID()+"/n")  print "Add student success!"  file1.close()  #Delete student menu  def delMenu():  print "1.Delete by ID"  print "2.Delete contains ID"  opt = raw_input("Select:")  if opt == "1":   delStudentByID()  elif opt == "2":   delStudentContainsID()  else:   print "Error input"     #Delete contains id   def delStudentContainsID():  contID = raw_input("ID:")  if getInfoContainsID(contID)==0 :   print "Can't find ID contains /"%s/" student" % contID   return  opt = raw_input("Are you sure delete all(Y/N):")  if not opt == "y" or opt == "Y":   return   f = open(FILEPATH,"r")  tmp = open(TEMPFILE,"a")  i=0  for eachLine in f:   items = eachLine.split("/t") #  if not re.match(contID, items[0]):   if items[0].count(contID) ==0:    tmp.write(eachLine)   else:    i+=1   f.close()  tmp.close()  os.remove(FILEPATH)  os.rename(TEMPFILE, FILEPATH)  print "Deleted %d data" % i  #get contains ID information     def getInfoContainsID(stuID):  f = open(FILEPATH)  i=0  for eachLine in f:   items = eachLine.split("/t")      if not items[0].count(stuID) ==0: #  if re.match(stuID,items[0]):    i+=1    if i==1:     print "ID/tNAME/tSEX/tCLASS"    print eachLine,  if i==0:   return 0  else :   return i  f.close()    #Delete student by ID  def delStudentByID():  delID = raw_input("Delete ID:")  if not isIDExist(delID) :   print "Can't find ID = %s student information" % delID   return    getInfoByID(delID)  opt = raw_input("Are you sure delete it(Y/N):")  if not (opt == "Y" or opt == "y"):   return    f = open(FILEPATH,"r")  tmp = open(TEMPFILE,"a")    for eachLine in f:   split = eachLine.split("/t")     if not delID == split[0]:    tmp.write(eachLine)       tmp.close()  f.close()  os.remove(FILEPATH)  os.rename(TEMPFILE, FILEPATH)  print "Delete success!"  #Query menu  def query():  print "1.Query student by ID"  print "2.Query all students"  opt = raw_input("Select:")  if opt == "1":   queryByID()  elif opt == "2":   queryAll()  #default is query all   elif opt == "":   queryAll()   else :   print "Error Input!"     #query ID exist def isIDExist(ID):  f = open(FILEPATH)  flag = 0  for eachline in f:   temp = eachline.split("/t")   if temp[0] == ID:    flag+=1  f.close()  if flag == 0 :   return False  else:   return True   #get information by ID for delete student  def getInfoByID(stuID):  f = open(FILEPATH)  i=0  for eachLine in f:   items = eachLine.split("/t")   if items[0] == stuID:    i+=1    if i==1:     print "ID/tNAME/tSEX/tCLASS"    print eachLine   f.close()     #Query student by ID def queryByID():  queryID = raw_input("ID:")  f = open(FILEPATH) # lines = f.readlines() # print lines[0].strip() # for line in lines: #  a = line.split() #  if queryID == a[1].strip(): #   print line.strip()  flag = 0  for eachline in f:   #split by "/t" get as C array temp[4]   temp = eachline.split("/t") #  print temp[0] , temp[1] , temp[2] , temp[3]   if temp[0] == queryID:    flag+=1    if flag == 1:     print "ID/tNAME/tSEX/tCLASS"    print eachline,  if flag == 0 :   print "Can't find ID = %s student information" % queryID    f.close() # f = open(FILEPATH) # readLines = f.readlines()   # for eachLine in f: #  eachLine #     #  if eachLine == queryID: #   print eachLine # f.close()  #Query all students  def queryAll():  f = open(FILEPATH,"r")  i=0  for eachLine in f:   i+=1   if i==1:    print "ID/tNAME/tSEX/tCLASS"   print eachLine,  f.close()  if i==0:   print "No data!"  def exitProgram():  print "Thank you Bye!" # sys.exit()   def init():  if os.path.exists(FILEPATH) :   print "Load file successful"  else:   try:    f = open(FILEPATH,"w")   except Exception:    print "Can't open file"    sys.exit()   finally:    f.close()   if __name__ == '__main__':  init()  menu()