《Python语言程序设计》课件-第一章（中英文课件）

Python语言程序设计【将数值转换成字符串】PythonLanguageProgramming[convertingnumericalvaluesintostrings]知识点【将数值转换成字符串】（Python2的用法）利用一对反撇（反撇和单引号不一样）【例】Python2用法a=123b=456c=a+bd='a与b作为字符连接：'+`a`+`b`print(c)print(d)【例】Python2和3共同用法(str())a=123b=456c=a+bd='a与b作为字符连接：'+str(a)+str(b)print(c)print(d)#579#a与b作为字符连接：123456#a与b作为字符连接：123456[Convertanumericvalueintoastring](UsageofPython2)Useapairofbackticks(backticksaredifferentfromsinglequotes)[Example]UsageofPython2a=123b=456c=a+bD='aandbareconnectedascharacters:'+`a`+`b`print(c)print(d)[Example]CommonusageofPython2and3(str())a=123b=456c=a+bD='aandbareconnectedascharacters:'+str(a)+str(b)print(c)print(d)#579#Aandbareconnectedascharacters:123456#Aandbareconnectedascharacters:123456KnowledgePointsPython语言程序设计【字符串的连接与倍增】PythonLanguageProgramming[Stringconcatenationandmultiplication]知识点【字符串的连接与倍增】字符串连接方式：直接用“+”来连接两个字符串，str1+str2【例】字符串连接方式1print(‘Deris’+‘Weng’)#

DerisWeng两个字符串用“逗号”隔开，但字符串之间会多出一个空格【例】字符串连接方式2print(‘Deris’，‘Weng’)#

DerisWeng[Stringconcatenationandmultiplication]Stringconnectionmethod:Connecttwostringsdirectlywith"+",str1+str2[Example]Stringconnectionmode1print(‘Deris’+‘Weng’)#

DerisWengThetwostringsareseparatedbycommas,butthereisanextraspacebetweenthestrings.[Example]Stringconnectionmode2print(‘Deris’，‘Weng’)#

DerisWengKnowledgePoints知识点【字符串的连接与倍增】字符串连接方式：两个字符串放在一起，中间有空格或者没有空格【例】字符串连接方式3print(‘Deris’‘Weng’)#

DerisWengprint(‘Deris’‘Weng’)#

DerisWeng用符号“%”连接一个字符串和一组变量【例】字符串连接方式4print('%s,%s'%('Deris','Weng'))#

Deris,WengStringconnectionmethod:Twostringsareputtogetherwithorwithoutspacesinthemiddle.[Example]StringConnectionMode3print(‘Deris’‘Weng’)#

DerisWengprint(‘Deris’‘Weng’)#

DerisWengConnectastringandasetofvariableswiththesymbol"%"[Example]StringConnectionMode4print('%s,%s'%('Deris','Weng'))#

Deris,Weng[Stringconcatenationandmultiplication]KnowledgePoints知识点【字符串的连接与倍增】字符串连接方式：利用字符串的函数join【例】字符串连接方式5var_list=['Deris','Weng','Female']a='***'print(a.join(var_list))#Deris***Weng***FemaleStringconnectionmethod:Usestringfunctionjoin[Example]Stringconnectionmode5var_list=['Deris','Weng','Female']a='***'print(a.join(var_list))#Deris***Weng***Female[Stringconcatenationandmultiplication]KnowledgePoints知识点【字符串的连接与倍增】字符串连接方式：字符串乘法，即字符串的倍增【例】字符串连接方式6a='Weng'print(a*3)#WengWengWengStringconnectionmethod:Stringmultiplication,thatis,themultiplicationofstrings[Example]StringConnectionMode6a='Weng'print(a*3)#WengWengWeng[Stringconcatenationandmultiplication]KnowledgePoints练习【字符串的连接与倍增】问题:

1.若定义a=‘A’，执行print(a*10)后，结果为

。2.若定义a=‘A’，b=‘B’，执行print(a+b)后，结果为

。3.若定义a=‘A’，b=‘B’，执行print(a，b)后，结果为

。4.若定义a=‘A’，b=‘B’，执行print(ab)后，结果为

。5.若定义a=‘A’，b=‘B’，执行print(ab)后，结果为

。practise[Stringconcatenationandmultiplication]Question:1.Ifa='A'isdefined,theresultisafterexecutingprint(a*10)

.2.Ifa='A'andb='B'aredefined,theresultisafterexecutingprint(a+b)

.3.Ifa='A'andb='B'aredefined,theresultisafterexecutingprint(a,b)

.4.Ifa='A'andb='B'aredefined,theresultisafterexecutingprint(ab)

.5.Ifa='A'andb='B'aredefined,theresultisafterexecutingprint(ab)

.Python语言程序设计【值与类型】PythonLanguageProgramming[ValueandType]知识点【值与类型】1.数字型：将数字分为：整数和带小数点的数。Python3支持int、float、complex（复数）。intfloatcomplex90.0123.45j999.991234.j-99-999.90.12e-34j0x123AB123EF99.9+e9912e+345jKnowledgePoints[ValueandType]1.Numericaltype:Dividenumbersintointegersandnumberswithdecimals.Python3supportint、float、complex.intfloatcomplex90.0123.45j999.991234.j-99-999.90.12e-34j0x123AB123EF99.9+e9912e+345j知识点【值与类型】观察数据的类型Python还提供了一个“内置函数”：type()用来观察数据的类型：若有定义a=3，执行print（type(a)）

之后，结果是：int。KnowledgePoints[ValueandType]ObservethetypeofdataPythonalsoprovidesa'built-infunction':Type()isusedtoobservethetypeofdata:Ifa=3isdefined,afterexecutingprint(type(a)),theresultis:int.知识点【值与类型】2.字符串【例】print（“这是一个‘单、双引号混合使用’的字符串示例”）【例】转义字符\的使用print('I\'m\"OK\"!')作用：如果字符串内部既包含单引号'又包含双引号"，可以用转义字符\来标识。KnowledgePoints[ValueandType]2.characterstring[Example]print("Thisisanexampleofastringthatusesacombinationofsingleanddoublequotationmarks")[Example]Useofescapecharacter“\”print('I\'m\"OK\"!')Function:Ifthestringcontainsbothsingleanddoublequotationmarksinside,theescapecharacter“\”canbeusedtoidentifyit.知识点【值与类型】3.布尔值（True、False）1234print(True)print(False)print(3>2)print(3>5)TrueFalseTrueFalse输出结果：1234print(TrueandTrue))print(Trueand

False)print(FalseandFalse)print(5>3and3>1)TrueFalseFalseTrue输出结果：KnowledgePoints[ValueandType]3.Booleanvalues(True,False)1234print(True)print(False)print(3>2)print(3>5)TrueFalseTrueFalseOutputresult:1234print(TrueandTrue))print(Trueand

False)print(FalseandFalse)print(5>3and3>1)TrueFalseFalseTrueOutputresult:知识点【值与类型】3.布尔值（True、False）1234print(Trueor

True)print(TrueorFalse)print(FalseorFalse)print(5>3or1>3)TrueTrueFalseTrue输出结果：123print(notTrue)print(notFalse)print(not1>2)FalseTrueTrue输出结果：KnowledgePoints[ValueandType]3.Booleanvalues(True,False)1234print(Trueor

True)print(TrueorFalse)print(FalseorFalse)print(5>3or1>3)TrueTrueFalseTrueOutputresult:123print(notTrue)print(notFalse)print(not1>2)FalseTrueTrueOutputresult:【例】布尔在条件判断中使用知识点【值与类型】3.布尔值1234ifage>=18:print('成年')else:print('未成年')KnowledgePoints[ValueandType]3.Booleanvalues[Example]Booleanisusedinconditionaljudgment1234ifage>=18:print('Adult')else:print('Minor')知识点【值与类型】空值是Python里一个特殊的值，用None表示。None不能理解为0，因为0是有意义的，而None是一个特殊的空值。4.空值Python还支持其他常用的数据类型，如：List（列表）、Tuple（元组）、Sets（集合）、Dictionary（字典）。5.其他数据类型KnowledgePoints[ValueandType]AnullvalueisaspecialvalueinPython,representedbyNone.Nonecannotbeunderstoodas0because0ismeaningful,whileNoneisaspecialnullvalue.Pythonalsosupportsothercommonlyuseddatatypes,suchasList,Tuple,Sets,Dictionary.5.Otherdatatypes4.Emptyvalue课后练习【值与类型】问题:

1.Python3的数字类型分为

、

、

等子类型。2.Python不支持的数据类型有（

）A.char B.int C.float D.listintcomplexfloatAAfter-schoolexercises[ValueandType]Question:

1.ThenumbertypesinPython3aredividedintosubtypessuchas

,

,

etc。2.ThedatatypesthatPythondoesnotsupportis(

)A.char B.int C.float D.listintcomplexfloatAPython语言程序设计【输入与输出】PythonLanguageProgramming[Inputandoutput]知识点【输入】变量＝input（“提示信息”）从键盘读取字符串是从用户处获取信息的一种最基本方式。123print('你叫什么名字')

name=input("我的名字是：")

print("你好！"+name.capitalize())【例】input()输入[Input]Variable=input("prompt")Readingstringsfromthekeyboardisthemostbasicwaytoobtaininformationfromtheuser.123Print('What'syourname')

Name=input("Mynameis:")

Print("Hello!"+name.capitalize())[Example]input()inputKnowledgePoints知识点【输入】【例】输入数值型的数据1234print("请输入你的幸运数字")

number=input("我的幸运数字是：")

numberNew=int(number)+10

print("祝你好运！"+str(numberNew))[Input][Example]Inputnumericdata1234Print("Pleaseenteryourluckynumber")

Number=input("Myluckynumberis:")

numberNew=int(number)+10

Print("Goodluck!"+str(numberNew))KnowledgePoints知识点【输出】print（输出一个字符串）在python中打印内容到命令行（或者叫终端、控制台）里面123print‘你要打印的东西’#或者print(‘你要打印的东西’)【例】Python2输出12print‘你要打印的东西’print(‘你要打印的东西’)【例】Python3输出[Output]Print(outputastring)Printcontenttothecommandline(orterminal,console)inPython123Print'Whatyouwanttoprint'#OrPrint('Whatyouwanttoprint')[Example]Python2output12Print'Whatyouwanttoprint'Print('Whatyouwanttoprint')[Example]Python3outputKnowledgePoints实用技巧【capitalize()、strip()】【例】capitalize()print("derisweng".capitalize())【例】strip()print("derisweng".strip())作用：使字符串中的第一个字符为大写，而其他字符为小写。作用：去掉开头和末尾的空白字符。Practicaltips【capitalize()、strip()】[Example]capitalize()print("derisweng".capitalize())[Example]strip()print("derisweng".strip())Function:Makethefirstcharacterinthestringuppercaseandtheothercharacterslowercase.Function:Removetheblankcharactersatthebeginningandattheend.实用技巧【dir()】【例】dir('')print(dir(''))作用：查看字符串包含哪些函数。['__add__','__class__','__contains__','__delattr__','__doc__','__eq__','__format__','__ge__','__getattribute__','__getitem__','__getnewargs__','__getslice__','__gt__','__hash__','__init__','__le__','__len__','__lt__','__mod__','__mul__','__ne__','__new__','__reduce__','__reduce_ex__','__repr__','__rmod__','__rmul__','__setattr__','__sizeof__','__str__','__subclasshook__','_formatter_field_name_split','_formatter_parser','capitalize','center','count','decode','encode','endswith','expandtabs','find','format','index','isalnum','isalpha','isdigit','islower','isspace','istitle','isupper','join','ljust','lower','lstrip','partition','replace','rfind','rindex','rjust','rpartition','rsplit','rstrip','split','splitlines','startswith','strip','swapcase','title','translate','upper','zfill']Practicaltips【dir()】[Example]dir('')print(dir(''))Function:Viewwhichfunctionsastringcontains['__add__','__class__','__contains__','__delattr__','__doc__','__eq__','__format__','__ge__','__getattribute__','__getitem__','__getnewargs__','__getslice__','__gt__','__hash__','__init__','__le__','__len__','__lt__','__mod__','__mul__','__ne__','__new__','__reduce__','__reduce_ex__','__repr__','__rmod__','__rmul__','__setattr__','__sizeof__','__str__','__subclasshook__','_formatter_field_name_split','_formatter_parser','capitalize','center','count','decode','encode','endswith','expandtabs','find','format','index','isalnum','isalpha','isdigit','islower','isspace','istitle','isupper','join','ljust','lower','lstrip','partition','replace','rfind','rindex','rjust','rpartition','rsplit','rstrip','split','splitlines','startswith','strip','swapcase','title','translate','upper','zfill']实用技巧【print技巧】【例】默认用空格分隔print('Hello','deris','weng')#

Helloderisweng【例】用字符串分隔print('Hello','deris','weng',sep=',')#Hello,deris,wengPracticaltips[PrintTechniques][Example]Defaultseparatedbyspacesprint('Hello','deris','weng')#

Helloderisweng[Example]Separatedbystringsprint('Hello','deris','weng',sep=',')#Hello,deris,weng实用技巧【print技巧】【例】在同一行打印123print('deris',end='')#通过指定结束字符为空字符串print('weng')#deriswengPracticaltips[PrintTechniques][Example]Printingonthesameline123Print('deris',end='')#Emptystringbyspecifyingtheendingcharacterprint('weng')#derisweng课后练习【输入与输出】问题:

1.若定义a=10,执行print(type(a))后，结果为

。2.若定义a=10.0,执行print(type(a))后，结果为

。3.三种基本的程序设计结构为

、

、

。4.圆的面积公式s=pi*r2，写成Python语言表达式为

。5.若定义a=97，执行print('a'+'8'+'3')后，结果为

。6.若定义a=97，执行print(a+'8'+'3')后，结果为

。7.若定义a=97，执行print(str(a)+'8'+'3')后，结果为

。8.若定义a=‘D’，执行print(a*10)后，结果为

。[Inputsandoutputs]Question:1.Ifa=10isdefined,afterexecutingprint(type(a)),theresultis

.2.Ifa=10.0isdefined,theresultisafterexecutingprint(type(a))

.3.Thethreebasicprogrammingstructuresare

,

,and

.4.Theareaformulaofcircles=pi*r2,writteninPythonlanguage,is

.5.Ifa=97isdefined,afterexecutingprint('a'+'8'+'3'),theresultis

.6.Ifa=97isdefined,afterexecutingprint(a+'8'+'3'),theresultis

.7.Ifa=97isdefined,afterexecutingprint(str(a)+'8'+'3'),theresultis

.8.Ifa='D'isdefined,theresultisafterexecutingprint(a*10)

.After-schoolexercisesPython语言程序设计【注释】PythonLanguageProgramming[Commentary]知识点【注释】单行注释-#开头形式单行注释-行末#形式多行注释-每行#开头[Commentary]Singlelinecomments-#beginningformSinglelinecomments-endofline#formMultilinecomments-eachlinestartswith#KnowledgePoints知识点【注释】！介绍一种特殊的多行注释多行注释-三重引号形式用“#”、“三重引号”表示注释，所有的注释是不执行的。注释总结[Commentary]！IntroducingaspecialtypeofmultilineannotationMultilinecomment-triplequotationmarkformUse"#","triplequotes"toindicatecomments,allcommentsarenotexecuted.AnnotatedsummaryKnowledgePoints课后练习【注释】提问考一考问题1：注释的方法是？问题2：注释里面的内容是不执行的，对or错？注释的方法：（1）#（2）

三重引号[Commentary]QUESTIONTakeatestQuestion1:Themethodofannotationis?Question2:Thecontentinthecommentisnotexecuted,rightorwrong?Methodsofcommenting:(1)#(2)triplequotesAfter-schoolexercisesPython语言程序设计【语句