TB-V4函数-说明-语法-参数-备注-示例.doc

分类索引数学函数9Abs9Acos9Acosh9Asin9Asinh10Atan10Atan210Atanh10Ceiling11Combin11Cos12Cosh12Ctan12Even12Exp12Fact13Floor13FracPart13IntPart14Ln14Log14Mod14Neg15Odd15Pi15Power15Rand16Round16RoundDown16RoundUp17Sign17Sin17Sinh17Sqr18Sqrt18Tan18Tanh18字符串函数19Exact19Left19Len19Lower19Mid20Right20Text20Trim20Upper20Value21颜色函数21Black21Blue21Cyan21DarkBrown21DarkCyan22DarkGray22DarkGreen22DarkMagenta22DarkRed22DefaultColor23Green23LightGray23Magenta23Red23Rgb24White24Yellow24时间函数24CurrentDate24CurrentTime25DateAdd25DateDiff25DateTimeToString25DateToString25Day26Friday26Hour26HourFromDateTime26MakeDate26MakeDateTime27MakeTime27MilliSecond27MilliSecondFromDateTime27Minute27MinuteFromDateTime28Monday28Month28MonthFromDateTime28Saturday28Second29SecondFromDateTime29StringToDate29StringToDateTime29StringToTime29Sunday30SystemDateTime30Thursday30TimeDiff30TimeToString30Tuesday31Wednesday31Weekday31WeekdayFromDateTime31Year31YearFromDateTime31数据函数32BarCount32BarStatus32C/Close32CurrentBar32D/Date33H/High33HistoryDataExist33L/Low33O/Open33OpenInt34T/Time34V/Vol34属性函数34BarInterval34BarType34BidAskSize35BigPointValue35CanMarketOrder35CanShortTrade36CanStopOrder36CanTrade36Category36ContractSize37ContractUnit37CurrencyName37CurrencySymbol37DataCount37ExchangeName38ExpiredDate38GetUserID38InitialMargin38MaintenanceMargin38MarginRatio39MaxBarsBack39MaxSingleTradeSize39MinMove39PriceScale39Symbol40SymbolName40SymbolType40行情函数40Q_AskPrice40Q_AskVol40Q_AvgPrice41Q_AskPriceFlag41Q_BidPrice41Q_BidPriceFlag41Q_BidVol41Q_BidVol42Q_High42Q_HisHigh42Q_HisLow42Q_InsideVol43Q_Last43Q_LastDate43Q_LastFlag43Q_LastTime43Q_LastVol44Q_Low44Q_LowerLimit44Q_Open44Q_OpenInt44Q_OpenIntFlag45Q_Oscillation45Q_OutsideVol45Q_PreOpenInt45Q_PreSettlePrice45Q_PriceChg46Q_PriceChgRatio46Q_TickChg46Q_TodayEntryVol46Q_TodayExitVol46Q_TotalVol47Q_TurnOver47Q_UpperLimit47QuoteDataExist47帐户函数47A_AccountID47A_BrokerID48A_BuyAvgPrice48A_BuyFreeze48A_BuyMargin48A_BuyPosition48A_BuyProfitLoss48A_CurrentEquity49A_DeleteOrder49A_FreeMargin49A_GetLastOpenOrderIndex50A_GetLastOrderIndex50A_GetOpenOrderCount50A_GetOrderCount51A_OpenOrderBuyOrSell51A_OpenOrderContractNo52A_OpenOrderEntryOrExit52A_OpenOrderFilledLot52A_OpenOrderFilledPrice53A_OpenOrderLot53A_OpenOrderPrice54A_OpenOrderStatus54A_OpenOrderTime54A_OrderBuyOrSell55A_OrderContractNo55A_OrderCanceledLot56A_OrderEntryOrExit56A_OrderFilledLot56A_OrderFilledPrice57A_OrderLot57A_OrderPrice57A_OrderStatus58A_OrderTime58A_PositionProfitLoss59A_PreviousEquity59A_ProfitLoss59A_SendOrder59A_SellAvgPrice60A_SellFreeze60A_SellMargin60A_SellPosition60A_SellProfitLoss60A_TodayBuyPosition61A_TodayDeposit61A_TodayDrawing61A_TodaySellPosition61A_TotalAvgPrice61A_TotalPosition62AccountDataExist62枚举函数62Enum_Buy62Enum_Canceled62Enum_Canceling63Enum_Declare63Enum_Declared63Enum_Deleted63Enum_Entry63Enum_Exit63Enum_ExitToday64Enum_Filled64Enum_FillPart64Enum_Sell64交易函数64Buy64BuyToCover65Sell65SellShort66其他函数67Alert67AlertEnabled67Commentary67FileAppend67FileDelete68FormulaName68GetGlobalVar68GetTBProfileString68GetTBProfileString2File68IIF69IIFString69InvalidInteger69InvalidNumeric69InvalidString70PlayWavSound70PlotBool70PlotNumeric70PlotString71SetGlobalVar71SetTBProfileString71SetTBProfileString2File72Unplot72策略性能72AvgBarsEvenTrade72AvgBarsLosTrade72AvgBarsWinTrade73GrossLoss73GrossProfit73LargestLosTrade73LargestWinTrade73MaxConsecLosers74MaxConsecWinners74MaxContractsHeld74NetProfit74NumEvenTrades74NumLosTrades74NumWinTrades75PercentProfit75TotalBarsEvenTrades75TotalBarsLosTrades75TotalBarsWinTrades75TotalTrades76策略状态76AvgEntryPrice76BarsSinceEntry76BarsSinceExit76BarsSinceLastEntry76ContractProfit77CurrentContracts77CurrentEntries77EntryDate77EntryPrice78EntryTime78ExitDate78ExitPrice78ExitTime79LastEntryDate79LastEntryPrice79LastEntryTime79MarketPosition79MaxContracts80MaxEntries80MaxPositionLoss80MaxPositionProfit80PositionProfit81组合性能81Portfolio_GrossLoss81Portfolio_GrossProfit81Portfolio_MaxDrawDown81Portfolio_MaxDrawDownRatio81Portfolio_NetProfit82Portfolio_PercentProfit82Portfolio_NumWinTrades82Portfolio_NumLossTrades82Portfolio_TotalTrades82组合状态83Portfolio_CurrentCapital83Portfolio_CurrentEntries83Portfolio_CurrentEquity83Portfolio_InitCapital83Portfolio_PositionProfit83Portfolio_TotalProfit84Portfolio_UsedMargin84字母索引A_AccountID43A_BrokerID43A_BuyAvgPrice44A_BuyFreeze44A_BuyMargin44A_BuyPosition44A_BuyProfitLoss44A_CurrentEquity44A_DeleteOrder45A_FreeMargin45A_GetLastOpenOrderIndex45A_GetLastOrderIndex46A_GetOpenOrderCount46A_GetOrderCount47A_OpenOrderBuyOrSell47A_OpenOrderContractNo47A_OpenOrderEntryOrExit48A_OpenOrderFilledLot48A_OpenOrderFilledPrice49A_OpenOrderLot49A_OpenOrderPrice49A_OpenOrderStatus50A_OpenOrderTime50A_OrderBuyOrSell50A_OrderCanceledLot51A_OrderContractNo51A_OrderEntryOrExit52A_OrderFilledLot52A_OrderFilledPrice52A_OrderLot53A_OrderPrice53A_OrderStatus53A_OrderTime54A_PositionProfitLoss54A_PreviousEquity54A_ProfitLoss55A_SellAvgPrice56A_SellFreeze56A_SellMargin56A_SellPosition56A_SellProfitLoss56A_SendOrder55A_TodayBuyPosition56A_TodayDeposit57A_TodayDrawing57A_TodaySellPosition57A_TotalAvgPrice57A_TotalPosition57Abs5AccountDataExist58Acos5Acosh5Alert62AlertEnabled62Asin5Asinh6Atan6Atan26Atanh6AvgBarsEvenTrade68AvgBarsLosTrade68AvgBarsWinTrade68AvgEntryPrice72BarCount28BarInterval30BarsSinceEntry72BarsSinceExit72BarsSinceLastEntry72BarStatus28BarType30BidAskSize31BigPointValue31Black17Blue17Buy60BuyToCover61C/Close28CanMarketOrder31CanShortTrade31CanStopOrder32CanTrade32Category32Ceiling7Combin7Commentary63ContractProfit73ContractSize32ContractUnit33Cos7Cosh8Ctan8CurrencyName33CurrencySymbol33CurrentBar28CurrentContracts73CurrentDate20CurrentEntries73CurrentTime20Cyan17D/Date28DarkBrown17DarkCyan17DarkGray18DarkGreen18DarkMagenta18DarkRed18DataCount33DateAdd21DateDiff21DateTimeToString21DateToString21Day22DefaultColor18EntryDate73EntryPrice73EntryTime74Enum_Buy58Enum_Canceled58Enum_Canceling58Enum_Declare58Enum_Declared59Enum_Deleted59Enum_Entry59Enum_Exit59Enum_ExitToday59Enum_Filled59Enum_FillPart60Enum_Sell60Even8Exact14ExchangeName33ExitDate74ExitPrice74ExitTime74Exp8ExpiredDate34Fact9FileAppend63FileDelete63Floor9FormulaName63FracPart9Friday22GetGlobalVar64GetTBProfileString64GetTBProfileString2File64GetUserID34Green19GrossLoss69GrossProfit69H/High29HistoryDataExist29Hour22HourFromDateTime22IIF64IIFString65InitialMargin34IntPart10InvalidInteger65InvalidNumeric65InvalidString65L/Low29LargestLosTrade69LargestWinTrade69LastEntryDate75LastEntryPrice75LastEntryTime75Left15Len15LightGray19Ln10Log10Lower15Magenta19MaintenanceMargin34MakeDate22MakeDateTime23MakeTime23MarginRatio34MarketPosition75MaxBarsBack35MaxConsecLosers69MaxConsecWinners69MaxContracts76MaxContractsHeld70MaxEntries76MaxPositionLoss76MaxPositionProfit76MaxSingleTradeSize35Mid15MilliSecond23MilliSecondFromDateTime23MinMove35Minute23MinuteFromDateTime24Mod10Monday24Month24MonthFromDateTime24Neg11NetProfit70NumEvenTrades70NumLosTrades70NumWinTrades70O/Open29Odd11OpenInt29PercentProfit71Pi11PlayWavSound65PlotBool66PlotNumeric66PlotString66Portfolio_CurrentCapital78Portfolio_CurrentEntries79Portfolio_CurrentEquity79Portfolio_GrossLoss77Portfolio_GrossProfit77Portfolio_InitCapital79Portfolio_MaxDrawDown77Portfolio_MaxDrawDownRatio77Portfolio_NetProfit77Portfolio_NumLossTrades78Portfolio_NumWinTrades78Portfolio_PercentProfit78Portfolio_PositionProfit79Portfolio_TotalProfit79Portfolio_TotalTrades78Portfolio_UsedMargin79PositionProfit76Power11PriceScale35Q_AskPrice36Q_AskPriceFlag37Q_AskVol36Q_AvgPrice36Q_BidPrice37Q_BidPriceFlag37Q_BidVol37Q_BidVol38Q_High38Q_HisHigh38Q_HisLow38Q_InsideVol38Q_Last39Q_LastDate39Q_LastFlag39Q_LastTime39Q_LastVol39Q_Low40Q_LowerLimit40Q_Open40Q_OpenInt40Q_OpenIntFlag40Q_Oscillation41Q_OutsideVol41Q_PreOpenInt41Q_PreSettlePrice41Q_PriceChg41Q_PriceChgRatio42Q_TickChg42Q_TodayEntryVol42Q_TodayExitVol42Q_TotalVol42Q_TurnOver43Q_UpperLimit43QuoteDataExist43Rand12Red19Rgb19Right16Round12RoundDown12RoundUp12Saturday24Second24SecondFromDateTime25Sell61SellShort62SetGlobalVar67SetTBProfileString67SetTBProfileString2File67Sign13Sin13Sinh13Sqr13Sqrt14StringToDate25StringToDateTime25StringToTime25Sunday25Symbol35SymbolName36SymbolType36SystemDateTime26T/Time30Tan14Tanh14Text16Thursday26TimeDiff26TimeToString26TotalBarsEvenTrades71TotalBarsLosTrades71TotalBarsWinTrades71TotalTrades71Trim16Tuesday26Unplot68Upper16V/Vol30Value16Wednesday27Weekday27WeekdayFromDateTime27White20Year27YearFromDateTime27Yellow20第 85 页 共 85 页数学函数Abs说明返回参数的绝对值。语法Numeric Abs(Numeric Number)参数Number 需要计算其绝对值的实数。备注返回参数的绝对值，参数绝对值是参数去掉正负号后的数值。示例Abs (2) = 2；Abs (-2) = 2；Abs (0) = 0；Abs (-5.3) = 5.3；Abs (10.43) = 10.43。Acos说明返回参数的反余弦值。语法Numeric Acos(Numeric Number)参数Number 角度的余弦值，必须介于 -11 之间。如果要用度表示反余弦值，需将结果再乘以 180/PI()。 备注返回数字的反余弦值。反余弦值为一个角度，而该角度的余弦值即为该函数的参数。返回的角度值以弧度表示，范围是0到Pi。示例Acos (-0.5) = 2.094395(2* Pi /3 弧度)；Acos (-0.5)*180/ Pi () = 120(度)。Acosh说明返回参数的反双曲余弦值。语法Numeric Acosh(Numeric Number)参数Number 大于等于 1 的实数。备注返回参数的反双曲余弦值。参数 Number 必须大于或等于 1。反双曲余弦值的双曲余弦即为该函数的参数，因此 Acosh (Cosh(Number) 等于 Number。示例Acosh (1) = 0；Acosh (10) = 2.993223。Asin说明返回参数的反正弦值。语法Numeric Asin(Numeric Number)参数Number 角度的正弦值，必须介于 -11 之间。备注返回参数的反正弦值。反正弦值为一个角度，该角度的正弦值即等于此函数的参数。返回角度的单位为弧度，且范围在 - Pi /2 到 Pi /2 之间。示例Asin (-0.5) = -0.5236 ( - Pi /6 弧度)；Asin (-0.5)*180/ Pi () = -30 (度)。Asinh说明返回参数的反双曲正弦值。语法Numeric Asinh(Numeric Number)参数Number 任意实数。备注返回参数的反双曲正弦值，反双曲正弦值的双曲正弦即等于此函数的参数值，因此，Asinh (Sinh( Number) 的值等于 Number。示例Asinh (-2.5) = -1.64723；Asinh (10) = 2.998223。Atan说明返回参数的反正切值。语法Numeric Atan(Numeric Number)参数Number 角度的正切值。备注返回参数的反正切值。反正切值为角度，其正切值即等于参数值。返回的角度值将以弧度表示，范围为 -pi/2 到 pi/2。如果要用度表示反正切值，需将结果再乘以 180/( )。示例Atan (1) = 0.785398(Pi /4 弧度)；Atan (1)*180/() = 45(度)。Atan2说明返回给定的 X 及 Y 坐标值的反正切值。语法Numeric Atan2(Numeric X_num,Numeric Y_num)参数X_num 点的 X 坐标。Y_num 点的 Y 坐标。 备注返回给定的 X 及 Y 坐标值的反正切值。反正切的角度值等于 X 轴与通过原点和给定坐标点（X_num, Y_num）的直线之间的夹角。结果以弧度表示并介于 - Pi到 Pi之间（不包括 - Pi）。结果为正表示从 X 轴逆时针旋转的角度，结果为负表示从X 轴顺时针旋转的角度。Atan2 (a, b) 等于 ATAN(b/a)，除非 Atan2值为零。如果 X_num 和 Y_num 都为零，Atan2返回无效值。如果要用度表示反正切值，需将结果再乘以 180/ Pi()。 示例Atan2 (1, 1) = 0.785398 (pi/4弧度)；Atan2 (-1, -1) = -2.35619 (-3* Pi /4 弧度)；Atan2 (-1, -1)*180/ Pi () = -135 (度)。 Atanh说明返回参数的反双曲正切值。语法Numeric Atanh(Numeric Number)参数Number -11 之间的任意实数。备注返回参数的反双曲正切值，参数必须在 -11 之间（除去 -1 和 1）。反双曲正切值的双曲正切即为该函数的参数值，因此 Atanh (Tanh(Number) 等于 Number。示例Atanh (0.76159416) = 1 （近似值）；Atanh (-0.1) = -0.10034。Ceiling说明将参数 Number 沿绝对值增大的方向，舍入为最接近的整数或基数Significance的最小倍数。语法Numeric Ceiling(Numeric Number,Numeric Significance)参数Number 待舍入的数值。Significance 基数。备注将参数 Number 沿绝对值增大的方向，舍入为最接近的整数或基数Significance的最小倍数。例如，如果您不愿意使用像分这样的零钱，而所要购买的商品价格为 $4.42，可以用公式 = Ceiling (4.42,0.1) 将价格舍入为以角表示。如果参数为非数值型，Ceiling返回无效值。无论数字符号如何，都按远离 0 点方向舍入。如果数字已经为 Significance 的倍数，则不进行舍入。如果 Number 和 Significance 符号不同，Ceiling返回无效值。示例Ceiling (2.5, 1) = 3；Ceiling (-2.5, -2) = -4；Ceiling (-2.5, 2) = 无效值；Ceiling (1.5, 0.1) = 1.5；Ceiling (0.234, 0.01) = 0.24。 Combin说明计算从给定数目的对象集合中提取若干对象的组合数。语法Integer Combin (Numeric Number,Numeric Number_chosen)参数Number 对象总的数量。Number_chosen 每一组合中对象的数量。备注数字参数截尾取整。如果任一参数为非数值型，Combin返回无效值。如果 number 0、number_chosen 0 或 number number_chosen，Combin返回无效值。对象组合是对象整体的任意子集，且不论其内部顺序。组合与排列不同，排列数与对象顺序有关。假设从 8 名候选者中选出 2 人组成一队，求所有可能的组合数：Combin (8, 2 ) 等于 28 种编队方案。 示例Combin(8, 2) = 28。 Cos说明返回给定角度的余弦值。语法Numeric Cos(Numeric Number)参数Number 为需要求余弦的角度，以弧度表示。如果参数的单位是度，则可以乘以Pi ()/180 将其转换为弧度。备注返回给定角度的余弦值。示例Cos (1.047) = 0.500171；Cos (60*Pi()/180) = 0.5，即 60 度的余弦值。Cosh说明返回参数的双曲余弦值。语法Numeric Cosh(Numeric Number)参数Number 表示要为其找到双曲线余弦的任意实数。 备注返回参数的双曲余弦值。示例Cosh (4) = 27.30823；Cosh (Exp(1) = 7.610125，式中 Exp(1) 等于 e，即自然对数的底数。Ctan说明返回给定角度的余切值。语法Numeric Ctan(Numeric Number)参数Number 需要计算其反余切值的实数。备注返回给定角度的余切值。示例Ctan (0.785) = 1.00080；Ctan (45* Pi ()/180) = 1。Even说明返回沿绝对值增大方向取整后最接近的偶数。语法Integer Even(Numeric Number)参数Number 所要取整的数值。备注返回沿绝对值增大方向取整后最接近的偶数。使用该函数可以处理那些成对出现的对象。如果 Number 为非数值参数，则 Even返回无效值。不论 Number 的正负号如何，函数都向远离零的方向舍入，如果 Number 恰好是偶数，则无需进行任何舍入处理。 示例Even (1.5) = 2；Even (3) = 4；Even (2) = 2；Even (-1) = -2。 Exp说明返回e的Number次幂。语法Numeric Exp(Numeric Number)参数Number 为底数e的指数。备注返回e的Number次幂。常数 e 等于 2.71828182845904，是自然对数的底数。如果要计算以其他常数为底的幂，请用指数操作符（）。Exp函数是计算自然对数的 Ln 函数的反函数。示例Exp (1) = 2.718282(e 的近似值)；Exp (2) = e2 或 7.389056；Exp (Ln(3) = 3。 Fact说明返回数的阶乘。语法Integer Fact(Numeric Number)参数Number 要计算其阶乘的非负数。如果输入的Number不是整数，则截尾取整。备注返回数的阶乘。示例Fact (1) = 1；Fact (1.9) = Fact (1) 等于 1；Fact (0) = 1；Fact (-1) = 无效值；Fact (5) = 1*2*3*4*5 等于 120。 Floor说明将参数 Number 沿绝对值减小的方向去尾舍入，使其等于最接近的 Significance 的倍数。语法Numeric Floor(Numeric Number,Numeric Significance)参数Number 所要舍入的数值。Significance 基数备注返将参数 Number 沿绝对值减小的方向去尾舍入，使其等于最接近的 significance 的倍数。如果任一参数为非数值参数，则Floor将返回错误值无效值。如果Number和Significance符号相反，则函数Floor将返回错误值无效值。不论Number的正负号如何，舍入时参数的绝对值都将减小。如果Number 恰好是significance 的倍数，则无需进行任何舍入处理。 示例Floor (2.5, 1) = 2；Floor (-2.5, -2) = -2；Floor (-2.5, 2) = 无效值；Floor (1.5, 0.1) = 1.5；Floor (0.234, 0.01) = 0.23。FracPart说明返回实数舍入后的小数值。语法Numeric FracPart(Numeric Number)参数Number 需要计算其小数值的实数。备注返回实数舍入后的小数值。等于 Number - IntPart(Number)。 示例FracPart (2.49) = 0.49；FracPart (-8.93) = 0.07。 IntPart说明返回实数舍入后的整数值。语法Integer IntPart(Numeric Number)参数Number 需要进行取整处理的实数。备注返回实数舍入后的整数值。 示例IntPart (8.9) = 8；IntPart (-8.9) = -9。 Ln说明返回一个数的自然对数。语法Numeric Ln(Numeric Number)参数Number 所要取整的数值。备注返回一个数的自然对数。自然对数以常数项 e（2.71828182845904）为底。Ln函数是Exp函数的反函数。 示例Ln (86) = 4.45437；Ln (2.7182818) = 1；Ln (Exp (3) = 3；Exp (Ln (4) = 4。 Log说明按所指定的底数，返回一个数的对数。语法Numeric Log(Numeric Number,Numeric Base)参数Number 为用于计算对数的正实数。Base 为对数的底数。 备注按所指定的底数，返回一个数的对数。示例Log (10，10) = 1；Log (8, 2) = 3；Log (86, 2.7182818) = 4.454347。 Mod说明返回两数相除的余数。语法Integer Mod(Integer Number,Integer Divisor)参数Number 为被除数。Divisor 为除数。如果Divisor为零，函数Mod返回无效值。 备注返回两数相除的余数。结果的正负号与除数相同。函数Mod可以借用函数IntPart来表示：Mod (n, d) = n - d*IntPart(n/d)。示例Mod (3, 2) = 1；Mod (-3, 2) = 1；Mod (3, -2) = -1；Mod (-3, -2) = -1。 Neg说明返回参数的负绝对值。语法Numeric Neg(Numeric Number)参数Number 需要计算其负绝对值的实数。备注返回参数的负绝对值，参数负绝对值是绝对值加上负号。示例Neg (2) = -2；Neg (-2) = -2；Neg (0) = 0 ；Neg (-5.3) = -5.3；Neg (10.43) = -10.43。 Odd说明返回对指定数值进行舍入后的奇数。语法Integer Odd(Numeric Number)参数Number 要舍入求奇数的数值。备注返回对指定数值进行舍入后的奇数。如果Number为非数值参数，函数Odd将返回无效值。不论正负号如何，数值都朝着远离0的方向舍入。如果Number恰好是奇数，则不须进行任何舍入处理。示例Odd (1.5) = 3；Odd (3) = 3；Odd (2) = 3；Odd (-1) = -1；Odd (-2) = -3。 Pi说明返回数字3.1415926535898。语法Numeric Pi()参数无备注返回数字3.1415926535898，即数学常数pi，精确到小数点后 13 位。示例无Power说明返回给定数字的乘幂。语法Numeric Power(Numeric Number,Numeric Power)参数Number 底数，可以为任意实数。Power 指数，Number按该指数次幂乘方。备注返回给定数字的乘幂。可以用运算符代替函数 Power来表示对底数乘方的幂次，例如 52。示例Power (5,2) = 25；Power (98.6,3.2) = 2401077；Power (4,5/4) = 5.656854。 Rand说明返回位于两个指定数之间的一个随机数。语法Numeric Rand(Numeric Bottom,Numeric Top)参数Bottom 函数Rand将返回的最小整数。Top 函数Rand将返回的最大整数。 备注返回位于两个指定数之间的一个随机数。每次计算都将返回一个新的数值。示例无Round说明返回某个数字按指定位数舍入后的数字。语法Numeric Round(Numeric Number,Integer Num_digits)参数Number 为需要向上舍入的任意实数。Num_digits 舍入后的数字的位数。备注返回某个数字按指定位数舍入后的数字。如果Num_digits大于0，则舍入到指定的小数位。如果Num_digits等于0，则舍入到最接近的整数。如果Num_digits小于0，则在小数点左侧进行舍入。 示例Round (2.15, 1) = 2.2；Round (2.149, 1) = 2.1；Round (-1.475, 2) = -1.48；Round (21.5, -1) = 20。 RoundDown说明靠近零值，向下（绝对值减小的方向）舍入数字。语法Numeric RoundDown(Numeric