Undefined function or variable using readtable and IF
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Hi there,
Im not sure why I am getting the error "UNDEFINED FUNCTION OR VARIABLE LANE1" at the end of the code where I am trying to assemble a table. Its obviously not looking at my, if Lanes == n, and I am not sure why. Here is the full code:
clear all
clc
%Percentage of different types of vehicles on roads
PercentageOfCars = 0.85 ;
PercentageOfBuses = 0.05 ;
PercentageOfTrucks = 0.10 ;
%Meters converted into miles
CarLength = 5 * 0.00062137;
BusLength = 10 * 0.00062137;
TruckLength = 15 * 0.00062137;
%Grabbing all data from excel file
DataSet = readtable('HighwayInformation.xls');
%Assinging variables from excel sheet
Mph = DataSet.SpeedLimitInMph;
SectionLength = DataSet.LengthOfTheSection_miles_;
Lanes = DataSet.NumberOfLanes;
BrakingDistanceCars = DataSet.CarBrakingDistance_miles_;
BrakingDistanceBuses = DataSet.BusBrakingDistance_miles_;
BrakingDistanceTrucks = DataSet.TruckBrakingDistance_miles_;
TimeToCompleteLane = (SectionLength ./ Mph); %Time in hours to complete respective section
TotalLengthWithLanes = SectionLength .* Lanes ; %Total length of section in miles
NumberOfVehiclesThatCanFitInLane = floor(SectionLength ./ (((BrakingDistanceCars + CarLength) * PercentageOfCars) + ((BrakingDistanceBuses + BusLength) * PercentageOfBuses) + ((BrakingDistanceTrucks + TruckLength) * PercentageOfTrucks)));
format shortg
PhasesOfVehicles = (1)./(TimeToCompleteLane);
MFV = (PhasesOfVehicles .* NumberOfVehiclesThatCanFitInLane);
%Lane 1 is inside lane
if Lanes == 2
Lane1 = MFV;
Lane2 = MFV * 0.95;
Lane3 = nan;
Lane4 = nan;
Lane5 = nan;
Lane6 = nan;
elseif Lanes == 3
Lane1 = MFV;
Lane2 = MFV * 0.95;
Lane3 = MFV * 0.90;
Lane4 = nan;
Lane5 = nan;
Lane6 = nan;
elseif Lanes == 4
Lane1 = MFV;
Lane2 = MFV * 0.95;
Lane3 = MFV * 0.90;
Lane4 = MFV * 0.85;
Lane5 = nan;
Lane6 = nan;
elseif Lanes == 5
Lane1 = MFV;
Lane2 = MFV * 0.95;
Lane3 = MFV * 0.90;
Lane4 = MFV * 0.85;
Lane5 = MFV * 0.80;
Lane6 = nan;
elseif Lanes == 6
Lane1 = MFV;
Lane2 = MFV * 0.95;
Lane3 = MFV * 0.90;
Lane4 = MFV * 0.85;
Lane5 = MFV * 0.80;
Lane6 = MFV * 0.75;
end
T = table(SectionLength,Mph,Lanes,Lane1,Lane2,Lane3,Lane4,Lane5,Lane6)
The rest of the code is working fine.
回答（1 个）
As the error message indicates, there is no variable (or function) named 'Lane1' which means "Lanes" does not equal 2,3,4,5, or 6. You could add a last "else" at the end of your conditionals to catch such errors.
else
error('''Lanes'' variable has unexpected value: %.3f', Lanes)
end
Also, if you're using discrete values, consider using a switch case instead.
%Lane 1 is inside lane
switch Lanes
case 2
Lane1 = MFV; %etc...
case 3
Lane1 = MFV;
case 4
Lane1 = MFV;
case 5
Lane1 = MFV;
case 6
Lane1 = MFV;
otherwise
error()
end
3 个评论
Daniel Pearson
2019-4-24
Adam Danz
2019-4-24
" Lanes is a 647x1 double supposedly".
The 'if' command operates on a scalar value, not a vector.
If you're testing whether ALL of the values are equal to 2,
if all(lanes==2)
If you're testing that ANY of the values equal 2,
if any(lanes==2)
If you're just interested in the first value of lanes,
if lanes(1)==2
Walter Roberson
2019-4-24
And if you want to process multiple entries in Lanes then you should use logical indexing.
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2019-4-24
2019-4-24
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