Home Error: Function 'subsindex' is not defined for values of class 'datetime'
 I am working in MatLab and have this script that calls an excel file and then converts them into MatLab form. Data=csvread('Group1LoadData.csv',1,0,[1,0,161675,21]); %Loads the data from a csv file date=Data(:,1)'; salePrice=Data(:,2)'; fuelCost=Data(:,3)'; Demand=Data(:,4)'; totalProd=Data(:,5)'; SteamSold=Data(:,6)'; turbine1Prod=Data(:,7)'; turbine1Fuel=Data(:,8)'; turbine1CO=Data(:,9)'; turbine1Nox=Data(:,10)'; turbine2Prod=Data(:,11)'; turbine2Fuel=Data(:,12)'; turbine2CO=Data(:,13)'; turbine2Nox=Data(:,14)'; db1Fuel=Data(:,15)'; db1Steam=Data(:,16)'; db2Fuel=Data(:,17)'; db2Steam=Data(:,18)'; steamProd=Data(:,19)'; steamFuel=Data(:,20)'; natGasDensity=Data(:,21)'; temp=Data(:,22)'; date=datetime(date,'ConvertFrom','excel');  What I am trying to do is create a new variable called "FuelCost" by calling the data from "fuelCost" in the previous code but only using specific dates, as shown. % Group1BEclcs tStart=date(:,40746); tEnd=date(:,43635); date_use=(tStart:tEnd); FuelCost=fuelCost(:,(date_use));  However, I keep getting an error displaying "Function 'subsindex' is not defined for values of class 'datetime'." What exactly does this mean?