Python进阶篇：文件系统的操作

  1 ‘‘‘
  2 编写可供查询的员工信息表--学号 姓名  年龄 班级
  3    1. 提供格式化查询接口
  4    2. 允许用户添加或者删除员工信息
  5 ‘‘‘
  6 import os
  7 employee_dir = ‘employee_list‘
  8 index=employee_dir+"/index"
  9 
 10 
 11 if(not os.path.exists(employee_dir)):
 12     os.mkdir(employee_dir,777)
 13 
 14 def add_student(id,name,age,_class):
 15     local_file = employee_dir+"/"+str(id)
 16     if(os.path.isfile(local_file)):
 17         print("id: %s 已经存在，请重新添加" %(id))
 18     else:
 19         f=open(local_file,"w")
 20         f.write(name+"\t"+str(age)+"\t"+_class)
 21         f.close()
 22         f=open(index,"a")
 23         f.write(str(id)+"\t"+name+"\n")
 24         f.close()
 25         print("id=%s添加成功" %id)
 26 
 27 def select_student(**kwargs):
 28     for key in kwargs.keys():
 29         if(key==‘id‘):
 30             local_file = employee_dir+"/"+str(kwargs[key])
 31             if(not os.path.isfile(local_file)):
 32                 print("不存在id:",kwargs[key])
 33             else:
 34                 f=open(local_file,"r")
 35                 print(kwargs[key],f.read())
 36         elif(key==‘name‘):
 37             if(not os.path.isfile(index)):
 38                 print("不存在name:",kwargs[key])
 39             else:
 40                 i=0
 41                 f=open(index,"r")
 42                 for line in f.readlines():
 43                     id,name = line.strip().split("\t")
 44                     if(name == kwargs[key]):
 45                         i=i+1
 46                         select_student(id=id)
 47                 if(i==0):
 48                     print("不存在name:",kwargs[key])
 49         else:
 50             print("无效的获取方式，只能通过id和name来获取!")
 51 
 52 
 53 def modify_student(id,name,age,_class):
 54     local_file = employee_dir+"/"+str(id)
 55     if(os.path.isfile(local_file)):
 56         os.remove(local_file)
 57         rm_line(index,id)
 58         add_student(id,name,age,_class)
 59         print("id=%s修改成功" %id)
 60     else:
 61         print("id: %s 不存在，请先添加" %(id))
 62 
 63 def delete_student(**kwargs):
 64     for key in kwargs.keys():
 65         if(key==‘id‘):
 66             local_file = employee_dir+"/"+str(kwargs[key])
 67             if(not os.path.isfile(local_file)):
 68                 print("不存在id:",kwargs[key],",无法删除")
 69             else:
 70                 os.remove(local_file)
 71                 rm_line(index,kwargs[key])
 72                 print("删除id=%s成功" %kwargs[key])
 73         elif(key==‘name‘):
 74             if(not os.path.isfile(index)):
 75                 print("不存在name:",kwargs[key],",无法删除")
 76             else:
 77                 i=0
 78                 f=open(index,"r")
 79                 for line in f.readlines():
 80                     id,name = line.strip().split("\t")
 81                     if(name == kwargs[key]):
 82                         i=i+1
 83                         delete_student(id=id)
 84                 if(i==0):
 85                     print("不存在name:",kwargs[key],",无法删除")
 86         else:
 87             print("无效的删除方式，只能通过id和name来删除!")
 88 
 89 def rm_line(file,id):
 90     if(not os.path.isfile(file)):
 91         print("不存在文件:",file)
 92     else:
 93         f= open(file,"r")
 94         of = open(file+".tmp","w")
 95         for line in f.readlines():
 96             localid,localname = line.strip().split("\t")
 97             if(str(id)==localid):
 98                 pass
 99             else:
100                 of.write(line,)
101         f.close()
102         of.close()
103         if(os.path.isfile(file+".tmpt")): os.remove(file+".tmpt")
104         os.rename(file,file+".tmpt")
105         os.rename(file+".tmp",file)