python学习实例（6）
【摘要】 #=============================#6.6 文件系统（File System）#============================= #+++++++++++++++++++++++++++++#6.6.3 Python中的文件操作#+++++++++++++++++++++++++++++ #<程序：读取文件os.py>f = o...
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#=============================
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#6.6 文件系统（File System）
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#=============================
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#+++++++++++++++++++++++++++++
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#6.6.3 Python中的文件操作
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#+++++++++++++++++++++++++++++
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#<程序：读取文件os.py>
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f = open("./Task1.txt",'r'); fls = f.readlines()
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for line in fls:
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line = line.strip(); print (line)
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f.close()
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#<程序：读取文件os.py，计算并写回>
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f = open("./Task1.txt",'r+'); fls = f.readlines()
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for line in fls:
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line = line.strip(); lstr = line.split()
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if lstr[0] == '3':
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res = 0
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for e in lstr[1:]:
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res+=int(e)
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f.write('\n4 '+str(res)); f.close()
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#+++++++++++++++++++++++++++++
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#6.6.4 学生实例4.6.3扩展
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#+++++++++++++++++++++++++++++
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#<程序：存储考试结果到class1.txt文件>
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class student:
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def __init__ (self,mname,studentID):
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self.name = mname; self.StuID = studentID; self.Course_Grade = {};
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self.Course_ID = []; self.GPA = 0; self.Credit = 0
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def selectCourse(self,CourseName,CourseID):
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self.Course_Grade[CourseID]=0; #CourseID:0 加入字典
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self.Course_ID.append(CourseID) # CourseID 加入列表
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self.Credit = self.Credit+ CourseDict[CourseID].Credit #总学分数更新
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def getInfo(self):
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print("Name:",self.name);print("StudentID",self.StuID);print("Course:")
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for courseID,grade in self.Course_Grade.items():
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print(CourseDict[courseID].courseName,grade)
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print("GPA",self.GPA); print("Credit",self.Credit); print("")
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def TakeExam(self, CourseID):
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self.Course_Grade[CourseID]=random.randint(50,100)
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self.calculateGPA()
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def Grade2GPA(self,grade):
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if(grade>=90):
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return 4
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elif(grade>=80):
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return 3
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elif(grade>=70):
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return 2
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elif(grade>=60):
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return 1
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else:
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return 0
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def calculateGPA(self):
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g = 0;
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#遍历每一门所修的课程
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for courseID,grade in self.Course_Grade.items():
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g = g + self.Grade2GPA(grade)* CourseDict[courseID].Credit
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self.GPA = round(g/self.Credit,2)
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class Course:
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def __init__ (self,cid,mname,CourseCredit,FinalDate):
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self.courseID = cid
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self.courseName = mname
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self.studentID = []
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self.Credit = CourseCredit
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self.ExamDate = FinalDate
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def SelectThisCourse(self,stuID): #记录谁修了这门课，在studentID列表里
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self.studentID.append(stuID)
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def setupCourse (CourseDict): #建立CourseList: list of Course objects
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CourseDict[1]=Course(1,"Introducation to Computer Science",4,1)
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CourseDict[2]=Course(2,"Advanced Mathematics",5,2)
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CourseDict[3]=Course(3,"Python",3,3)
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CourseDict[4]=Course(4,"College English",4,4)
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CourseDict[5]=Course(5,"Linear Algebra",3,5)
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def setupClass (StudentDict): #输入一个空列表
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NameList = ["Aaron","Abraham","Andy","Benson","Bill","Brent","Chris","Daniel",
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"Edward","Evan","Francis","Howard","James","Kenneth","Norma","Ophelia","Pearl",
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"Phoenix","Prima","XiaoMing"]
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stuid = 1
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for name in NameList:
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StudentDict [stuid]=student(name,stuid) #student对象的字典
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stuid = stuid + 1
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def SelectCourse (StudentList, CourseList):
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for stu in StudentList: #每一个学生修几门课
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CourseNum = random.randint(3,len(CourseList)) #修CourseNum数量的课
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#随机选，返回列表
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CourseIndex = random.sample(range(len(CourseList)), CourseNum)
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for index in CourseIndex:
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stu.selectCourse(CourseList[index].courseName,CourseList[index].Credit)
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CourseList[index].SelectThisCourse(stu.StuID)
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def ExamSimulation (StudentList, CourseList):
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for day in range(1,6): #Simulate the date
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for cour in CourseList:
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if(cour.ExamDate==day): # Hold the exam of course on that day
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for stuID in cour.studentID:
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for stu in StudentList:
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if(stu.StuID == stuID): #student stuID selected this course
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stu.TakeExam(cour.courseID)
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import random
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CourseDict={}
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StudentDict={}
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setupCourse(CourseDict)
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setupClass(StudentDict)
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SelectCourse(list(StudentDict.values()),list(CourseDict.values()))
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ExamSimulation(list(StudentDict.values()),list(CourseDict.values()))
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SaveToFile = ["ID"," ","Name"," ","Credit"," ","GPA","\n"]
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for stu in StudentDict.values():
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SaveToFile.append(str(stu.StuID))
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SaveToFile.append(" ")
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SaveToFile.append(str(stu.name))
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SaveToFile.append(" ")
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SaveToFile.append(str(stu.Credit))
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SaveToFile.append(" ")
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SaveToFile.append(str(stu.GPA))
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SaveToFile.append("\n")
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f = open("class1.txt","w")
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f.writelines(SaveToFile)
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f.close()
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#<程序：查询文件class1.txt中满足某条件的学生信息>
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def select(path,col,op,val):
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f = open(path,"r")
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colNum = 0
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if col == "ID": colNum = 0
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elif col == "Name": colNum = 1
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elif col == "Credit": colNum = 2
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elif col == "GPA": colNum = 3
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f.readline()
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Info = f.readlines()
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res = []
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for e in Info:
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e = e.strip()
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eList = e.split()
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if colNum != 1:
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exp = eList[colNum] + op + val
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else:
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exp = "'" + eList[colNum] + "'" + op + "'" + val + "'"
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if eval(exp):
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res.append(e)
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f.close()
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return res
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for e in select("class1.txt","Credit",">=","15"):
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print (e)
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#<程序：对文件class1.txt中学生进行排序>
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def sort(path,col,direct):
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#direct表示排序方向，">"为从大到小排序，"<"相反。
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colNum = 0
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if col == "Credit": colNum = 2
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elif col == "GPA": colNum = 3
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ifrev = False
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if direct == ">":ifrev = True
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f = open(path,"r")
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f.readline()
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Info = f.readlines()
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res = []
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for e in Info:
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eList = e.split()
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res.append(eList)
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res =sorted(res, key=lambda res: res[colNum],reverse=ifrev)
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#第三个参数为排序方向
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f.close()
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return res
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L = [('b',2),('a',1),('c',3),('d',4)]
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print (sorted(L, key=lambda x:x[1]))
文章来源: fantianzuo.blog.csdn.net，作者：兔老大RabbitMQ，版权归原作者所有，如需转载，请联系作者。
原文链接：fantianzuo.blog.csdn.net/article/details/83025226
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