Delphi_HELP函数集.doc

HELP函数集-abs(x)绝对值arctan(x)反正切cos(x)传回馀弦函数值exp(x)e的x次幂frac(x)取小数部分int(x)取整ln(x)自然对数sin(x)传回正弦函数值sqr(x)x*xsqrt(x)平方根其它pred(x)pred(D)=C,pred(true)=1;succ(x)succ(Y)=Z,succ(pred(x)=xord(x)求x在字符集中的序号,如ord(A)=65chr(x)chr(65)=Around(x)四舍五入trunc(x)trunc(4.8)=4,trunc(-3.6)=-3upcase(x)upcase(a)=Ahi(I)hi($2A30)=$2Alo(I)lo($2A30)=$30random(n)产生0,n)间的随机整数sizeof(name)求出某类型或变量在内存中占用的字节数swap(num)swap($3621)=$2136=Arithmeticroutines数学运算=Abs绝对值-UnitSystem函数原型functionAbs(X);说明X为整数or实数.范例varr:Real;i:Integer;beginr:=Abs(-2.3);2.3i:=Abs(-157);157end;-ArcTan三角函数-范例CosvarR:Extended;beginR:=Cos(Pi);end;-Sin-范例varR:Extended;S:string;beginR:=Sin(Pi);Str(R:5:3,S);Canvas.TextOut(10,10,TheSinofPiis+S);end;-UnitSystem函数原型functionArcTan(X:Extended):Extended;函数原型functionCos(X:Extended):Extended;函数原型functionSin(X:Extended):Extended;-说明X为径度.Tan(x)=Sin(x)/Cos(x)ArcSin(x)=ArcTan(x/sqrt(1-sqr(x)ArcCos(x)=ArcTan(sqrt(1-sqr(x)/x)左边这三个不是函数,而是右边运算求得.范例varR:Extended;beginR:=ArcTan(Pi);end;范例varR:Extended;S:string;beginR:=Sin(Pi);Str(R:5:3,S);Canvas.TextOut(10,10,TheSinofPiis+S);end;-Frac求一个实数的小数部份-UnitSystem函数原型functionFrac(X:Real):Real;说明X为实数.范例varR:Real;beginR:=Frac(123.456);0.456R:=Frac(-123.456);-0.456end;-Int求一个实数的整数部份-UnitSystem函数原型functionInt(X:Real):Real;说明X为实数.范例varR:Real;beginR:=Int(123.456);123.0R:=Int(-123.456);-123.0end;-Pi就是数学的Pi-UnitSystem函数原型functionPi:Extended;说明它是一个函数,但我们就把它当作是预设的变数来用吧!Pi=3.1415926535897932385-SqrX的平方-范例varS,Temp:string;beginStr(Sqr(5.0):3:1,Temp);S:=5squaredis+Temp+#13#10;Str(Sqrt(2.0):5:4,Temp);S:=S+Thesquarerootof2is+Temp;MessageDlg(S,mtInformation,mbOk,0);end;-SqrtX的平方根-UnitSystem函数原型functionSqr(X:Extended):Extended;函数原型functionSqrt(X:Extended):Extended;范例varS,Temp:string;beginStr(Sqr(5.0):3:1,Temp);S:=5squaredis+Temp+#13#10;Str(Sqrt(2.0):5:4,Temp);S:=S+Thesquarerootof2is+Temp;MessageDlg(S,mtInformation,mbOk,0);end;-Ln自然对数-范例vare:real;S:string;begine:=Exp(1.0);Str(ln(e):3:2,S);S:=e=+FloatToStr(e)+;ln(e)=+S;Canvas.TextOut(10,10,S);end;-Exp指数-UnitSystem函数原型functionLn(X:Real):Real;函数原型functionExp(X:Real):Real;范例vare:real;S:string;begine:=Exp(1.0);Str(ln(e):3:2,S);S:=ln(e)=+S;Canvas.TextOut(10,10,S);end;-Dateandtimeroutines日期及时间函数-Date传回目前的日期UnitSysUtils函数原型functionDate:TDateTime;范例procedureTForm1.Button1Click(Sender:TObject);beginLabel1.Caption:=Todayis+DateToStr(Date);end;-DateTimeToStr日期时间转换成内定型字串(1996/12/2009:12:20PM)-UnitSysUtils函数原型functionDateTimeToStr(DateTime:TDateTime):string;范例procedureTForm1.Button1Click(Sender:TObject);beginLabel1.Caption:=DateTimeToStr(Now);end;-DateTimeToString日期时间转换成自定型字串-UnitSysUtils函数原型procedureDateTimeToString(varResult:string;constFormat:string;DateTime:TDateTime);范例procedureTForm1.FormCreate(Sender:TObject);vars:string;beginDateTimeToString(s,dddd,mmmmd,yyyyathh:mmAM/PM,Now);Label1.Caption:=s;end;结果星期五,十二月20,1996at09:20PM-*Format格式叁考下面.FormatDateTime.-DateToStr日期转换成内定型字串.(1996/12/20)-UnitSysUtils函数原型functionDateToStr(Date:TDateTime):string;范例procedureTForm1.Button1Click(Sender:TObject);beginLabel1.Caption:=Todayis+DateToStr(Date);end;#Date,DateToStrExample-DayOfWeek求叁数日期是星期几.-UnitSysUtils函数原型functionDayOfWeek(Date:TDateTime):Integer;说明传回值是一整数,17.星期日为1.范例procedureTForm1.Button1Click(Sender:TObject);varADate:TDateTime;days:array1.7ofstring;begindays1:=Sunday;days2:=Monday;days3:=Tuesday;days4:=Wednesday;days5:=Thursday;days6:=Friday;days7:=Saturday;ADate:=StrToDate(Edit1.Text);ShowMessage(Edit1.Text+isa+daysDayOfWeek(ADate);end;#StrToDate,DayOfWeekExample-DecodeDate将TDateTime型态的日期变数，转为Word型态.-范例procedureTForm1.Button1Click(Sender:TObject);varPresent:TDateTime;Year,Month,Day,Hour,Min,Sec,MSec:Word;beginPresent:=Now;DecodeDate(Present,Year,Month,Day);Label1.Caption:=TodayisDay+IntToStr(Day)+ofMonth+IntToStr(Month)+ofYear+IntToStr(Year);DecodeTime(Present,Hour,Min,Sec,MSec);Label2.Caption:=ThetimeisMinute+IntToStr(Min)+ofHour+IntToStr(Hour);end;#DecodeDate,DecodeTimeExample-DecodeTime将TDateTime型态的时间变数，转为Word型态.-UnitSysUtils函数原型procedureDecodeDate(Date:TDateTime;varYear,Month,Day:Word);函数原型procedureDecodeTime(Time:TDateTime;varHour,Min,Sec,MSec:Word);范例procedureTForm1.Button1Click(Sender:TObject);varPresent:TDateTime;Year,Month,Day,Hour,Min,Sec,MSec:Word;beginPresent:=Now;DecodeDate(Present,Year,Month,Day);Label1.Caption:=TodayisDay+IntToStr(Day)+ofMonth+IntToStr(Month)+ofYear+IntToStr(Year);DecodeTime(Present,Hour,Min,Sec,MSec);Label2.Caption:=ThetimeisMinute+IntToStr(Min)+ofHour+IntToStr(Hour);end;-EncodeDate将Word型态的日期变数，转为TDateTime型态.-范例procedureTForm1.Button1Click(Sender:TObject);varMyDate:TDateTime;beginMyDate:=EncodeDate(StrToInt(Edit1.Text),StrToInt(Edit2.Text),StrToInt(Edit3.Text);Label1.Caption:=DateToStr(MyDate);end;-EncodeTime将Word型态的时间变数，转为TDateTime型态.-UnitSysUtils函数原型functionEncodeDate(Year,Month,Day:Word):TDateTime;函数原型functionEncodeTime(Hour,Min,Sec,MSec:Word):TDateTime;范例procedureTForm1.Button1Click(Sender:TObject);varMyDate:TDateTime;MyTime:TDateTime;beginMyDate:=EncodeDate(83,12,31);Label1.Caption:=DateToStr(MyDate);MyTime:=EncodeTime(0,45,45,7);Label2.Caption:=TimeToStr(MyTime);end;范例procedureTForm1.Button1Click(Sender:TObject);varMyTime:TDateTime;beginMyTime:=EncodeTime(0,45,45,7);Label1.Caption:=TimeToStr(MyTime);end;-FormatDateTime将日期时间依Format的格式转换给一字串.-UnitSysUtils函数原型functionFormatDateTime(constFormat:string;DateTime:TDateTime):string;*类似DateTimeToString.Format格式c内定值ShortDateFormat的格式.(1996/12/2009:20:15PM).d日期,前面不补0.(1-31)dd日期,前面补0.(01-31)ddd星期.(星期日).Dddd中文2.01版,同上.ddddd日期.(1996/12/20)dddddd日期.(1996年12月20日)m月份,前面不补0.(1-12)mm月份,前面补0.(01-12)mmm中文显示.(十二月)mmmm中文2.01版,同上.Yy年度.(00-99)yyyy年度.(0000-9999)h小时.(0-23)hh小时.(00-23)n分钟.(0-59)nn分钟.(00-59)s秒钟.(0-59)ss秒钟.(00-59)t时间.(09:20PM)tt时间.(09:20:15PM)am/pm单独显示amorpm.(若大写,则显示大写)a/p单独显示aorp.范例ThefollowingexampleassignsThemeetingisonWednesday,February15,1995at10:30AMtothestringvariableS.S:=FormatDateTime(Themeetingisondddd,mmmmd,yyyy,athh:mmAM/PM,StrToDateTime(2/15/9510:30am);/?-Now传回目前的日期时间.-UnitSysUtils函数原型functionNow:TDateTime;范例procedureTForm1.Button1Click(Sender:TObject);beginLabel1.Caption:=DateTimeToStr(Now);end;#Now,DateTimeToStrExample-StrToDate将字串转为TDateTime型态的日期.-UnitSysUtils函数原型functionStrToDate(constS:string):TDateTime;范例procedureTForm1.Button1Click(Sender:TObject);varADate:TDateTime;beginADate:=StrToDate(Edit1.Text);Label1.Caption:=DateToStr(ADate);end;范例procedureTForm1.Button1Click(Sender:TObject);varADate:TDateTime;days:array1.7ofstring;begindays1:=Sunday;days2:=Monday;days3:=Tuesday;days4:=Wednesday;days5:=Thursday;days6:=Friday;days7:=Saturday;ADate:=StrToDate(Edit1.Text);ShowMessage(Edit1.Text+isa+daysDayOfWeek(ADate);end;#StrToDate,DayOfWeekExample-StrToDateTime将字串转为TDateTime型态的日期时间.-UnitSysUtils函数原型functionStrToDateTime(constS:string):TDateTime;范例procedureTForm1.Button1Click(Sender:TObject);varADateAndTime:TDateTime;beginADateAndTime:=StrToDateTime(Edit1.Text);Table1.FieldByName(TimeStamp).AsDateTime:=ADateAndTime;end;-StrToTime将字串转为TDateTime型态的时间.-UnitSysUtils函数原型functionStrToTime(constS:string):TDateTime;范例procedureTForm1.Button1Click(Sender:TObject);varATime:TDateTime;beginATime:=StrToTime(Edit1.Text);ifATime0.50thenShowMessage(GoodMorning)elseShowMessage(GoodAfternoon);end;-Time传回目前的时间.-UnitSysUtils函数原型functionTime:TDateTime;范例procedureTForm1.Timer1Timer(Sender:TObject);varDateTime:TDateTime;str:string;beginDateTime:=Time;/storethecurrentdateandtimestr:=TimeToStr(DateTime);/convertthetimeintoastringCaption:=str;/displaythetimeontheformscaptionNoteThiscouldhavebeendonewiththefollowinglineofcode:Caption:=TimeToStr(Time);end;#Time,TimeToStrExample-TimeToStr时间转换成内定型字串.(09:20:15PM)-UnitSysUtils函数原型functionTimeToStr(Time:TDateTime):string;GetMemprocedure配置记忆体程序New配置指位器P的记忆体空间，大小为P所指型态的大小.-Dispose释放New所配置的记忆体.-UnitSystem函数原型procedureNew(varP:Pointer);函数原型procedureDispose(varP:Pointer);范例typePListEntry=TListEntry;TListEntry=recordNext:PListEntry;Text:string;Count:Integer;end;varList,P:PListEntry;begin.New(P);P.Next:=List;P.Text:=Helloworld;P.Count:=1;List:=P;.Dispose(P);end;范例typeStr18=string18;varP:Str18;beginNew(P);P:=Nowyouseeit.;Dispose(P);Nowyoudont.end;-GetMem配置指位器P的记忆体空间，大小可自行设定.-范例varF:file;Size:Integer;Buffer:PChar;beginAssignFile(F,test.txt);Reset(F,1);trySize:=FileSize(F);GetMem(Buffer,Size);tryBlockRead(F,Buffer,Size);ProcessFile(Buffer,Size);finallyFreeMem(Buffer);end;finallyCloseFile(F);end;end;-FreeMem释放GetMem所配置的记忆体.-UnitSystem函数原型procedureGetMem(varP:Pointer;Size:Integer);函数原型procedureFreeMem(varP:Pointer;Size:Integer);范例varF:file;Size:Integer;Buffer:PChar;beginAssignFile(F,test.txt);Reset(F,1);trySize:=FileSize(F);GetMem(Buffer,Size);tryBlockRead(F,Buffer,Size);ProcessFile(Buffer,Size);finallyFreeMem(Buffer);end;finallyCloseFile(F);end;end;=File-managementroutines档案管理常式=-ChangeFileExt变更档案的副档名-UnitSysUtils函数原型functionChangeFileExt(constFileName,Extension:string):string;范例procedureTForm1.Button1Click(Sender:TObject);varS:String;P1:String;P2:String;beginP1:=abc.txt;P2:=.ini;S:=ChangeFileExt(P1,P2);Label1.Caption:=S;end;结果S=abc.iniP1:=abcP2:=.iniS=abc.iniP1:=c:windowsabc.txtP2:=.iniS=c:windowsabc.iniP1:=abc.txtP2:=iniS=abcini*注意:P2的第一位元必须有一点.ini范例procedureTForm1.ConvertIcon2BitmapClick(Sender:TObject);vars:string;Icon:TIcon;beginOpenDialog1.DefaultExt:=.ICO;OpenDialog1.Filter:=icons(*.ico)|*.ICO;OpenDialog1.Options:=ofOverwritePrompt,ofFileMustExist,ofHideReadOnly;ifOpenDialog1.ExecutethenbeginIcon:=TIcon.Create;tryIcon.Loadfromfile(OpenDialog1.FileName);s:=ChangeFileExt(OpenDialog1.FileName,.BMP);Image1.Width:=Icon.Width;Image1.Height:=Icon.Height;Image1.Canvas.Draw(0,0,Icon);Image1.Picture.SaveToFile(s);ShowMessage(OpenDialog1.FileName+Savedto+s);finallyIcon.Free;end;end;end;#SaveToFile,Create,Height,Width,Canvas,ChangeFileExtexample-ExpandFileName将档案名称加在目前所在之路径全名之後-UnitSysUtils函数原型functionExpandFileName(constFileName:string):string;说明设目前目录为c:windows档案名称为abc.txt则结果为c:windowsabc.txt*此函数并不是求abc.txt的所在路径.范例procedureTForm1.Button1Click(Sender:TObject);varS:String;beginS:=ExpandFileName(abc.txt);Label1.Caption:=S;end;范例procedureTForm1.Button1Click(Sender:TObject)beginListBox1.Items.Add(ExpandFileName(Edit1.Text);end;-DirectoryExists目录是否存在-UnitFileCtrlusesFileCtrl;procedureTForm1.Button1Click(Sender:TObject);beginifnotDirectoryExists(c:temp)thenifnotCreateDir(C:temp)thenraiseException.Create(Cannotcreatec:temp);end;-ForceDirectories目录-UnitFileCtrl函数原型functionForceDirectories(Dir:string):Boolean;procedureTForm1.Button1Click(Sender:TObject);varDir:string;beginDir:=C:APPSSALESLOCAL;ifDirectoryExists(Dir)thenLabel1.Caption:=Dir+wascreatedend;-ExpandUNCFileName同上(只是得到网路上的路径)-UnitSysUtils函数原型functionExpandUNCFileName(constFileName:string):string;ExtractFileDir分析字串中的路径UnitSysUtils函数原型functionExtractFileDir(constFileName:string):string;说明设S字串为c:windowsabc.txt则结果为c:windows*功能在於由任何部份传来的叁数,加以分析它的路径范例procedureTForm1.Button1Click(Sender:TObject);varS:String;P1:String;beginP1:=c:windowsabc.txt;S:=ExtractFileDir(P1);Label1.Caption:=S;end;S=c:windowsP1:=abc.txtS=P1:=c:abc.txtS=c:P1:=c:abc.txtS=c:-ExtractFileDrive分析字串中的磁碟机名称-UnitSysUtils函数原型functionExtractFileDrive(constFileName:string):string;*功能同上,只是传回磁碟机名称.范例procedureTForm1.Button1Click(Sender:TObject);varS:String;P1:String;beginP1:=c:windowsabc.txt;S:=ExtractFileDrive(P1);Label1.Caption:=S;end;S:=c:P1:=abc.txtS=-ExtractFileExt分析字串中的档案名称的副档名-UnitSysUtils函数原型functionExtractFileExt(constFileName:string):string;范例procedureTForm1.Button1Click(Sender:TObject);varS:String;P1:String;beginP1:=c:windowsabc.txt;S:=ExtractFileExt(P1);Label1.Caption:=S;end;S=.txtP1:=c:windowsabcS=范例MyFilesExtension:=ExtractFileExt(MyFileName);-ExtractFileName分析字串中的档案名称(只传回档案名称)-UnitSysUtils函数原型functionExtractFileName(constFileName:string):string;范例procedureTForm1.Button1Click(Sender:TObject);varS:String;P1:String;beginP1:=c:windowsabc.txt;S:=ExtractFileName(P1);Label1.Caption:=S;end;S=abc.txt范例procedureTForm1.Button1Click(Sender:TObject);varBackupName:string;FileHandle:Integer;StringLen:Integer;X:Integer;Y:Integer;beginifSaveDialog1.ExecutethenbeginifFileExists(SaveDialog1.FileName)thenbeginBackupName:=ExtractFileName(SaveDialog1.FileName);BackupName:=ChangeFileExt(BackupName,.BAK);ifnotRenameFile(SaveDialog1.FileName,BackupName)thenraiseException.Create(Unabletocreatebackupfile.);end;FileHandle:=FileCreate(SaveDialog1.FileName);Writeoutthenumberofrowsandcolumnsinthegrid.FileWrite(FileHandle,StringGrid1.ColCount,SizeOf(StringGrid1.ColCount);FileWrite(FileHandle,StringGrid1.RowCount,SizeOf(StringGrid1.RowCount);forX:=0toStringGrid1.ColCount?1dobeginforY:=0toStringGrid1.RowCount?1dobeginWriteoutthelengthofeachstring,followedbythestringitself.StringLen:=Length(StringGrid1.CellsX,Y);FileWrite(FileHandle,StringLen,SizeOf(StringLen);FileWrite(FileHandle,StringGrid1.CellsX,Y,Length(StringGrid1.CellsX,Y);end;end;FileClose(FileHandle);end;end;#FileExists,RenameFile,FileCreate,FileWrite,