How do I stop the loop from overwriting JtD2017?

date = EcoTotemBroadwayBicycleCount(:,1);
DateTime = table2array(date);
FMTDate = datetime(DateTime,'InputFormat','MM/dd/yyyy HH:mm:ss a');
CyclistAmt = EcoTotemBroadwayBicycleCount(:,5);
DateNum = datevec(FMTDate);
DateNum(:,7) = [0];
A = table2array(CyclistAmt);
DateNum(:,7) = [A];
%%
idx = DateNum(:,1)==2017;
Year2017 = DateNum(idx,:);
i = 1;

for i = 1:1:12
    inx2 = Year2017(:,2)==i;
    JtD2017 = Year2017(inx2,:)
    JtD2017Cyl =JtD2017(:,7);
    MonthlyData2017(i) =sum(JtD2017Cyl);
    Med2017(i)= median(JtD2017Cyl);
end
%%
bar(MonthlyData2017)
title('2017 Data')
xlabel('Month')
ylabel('No. of Cyclists')

[Image Analyst]

You need to index it, like

JtD2017(i, 1:size(Year2017, 2)) = Year2017(inx2,:)

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[Shiva]

Thank you for the help, i ran into this error :

Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

Error in Quiz2Things(1) (line 15)

JtD2017(i, 1:size(Year2017, 2)) = Year2017(inx2,:)

date = EcoTotemBroadwayBicycleCount1(:,1);
DateTime = table2array(date);
FMTDate = datetime(DateTime,'InputFormat','MM/dd/yyyy HH:mm:ss a');
CyclistAmt = EcoTotemBroadwayBicycleCount(:,5);
DateNum = datevec(FMTDate);
DateNum(:,7) = [0];
A = table2array(CyclistAmt);
DateNum(:,7) = [A];
%%
idx = DateNum(:,1)==2017;
Year2017 = DateNum(idx,:);
i = 1;
for i = 1:1:12
    inx2 = Year2017(:,2)==i;
    JtD2017(i, 1:size(Year2017, 2)) = Year2017(inx2,:)
    JtD2017Cyl =JtD2017(:,7);
    MonthlyData2017(i) =sum(JtD2017Cyl);
    Med2017(i)= median(JtD2017Cyl);
end
%%
bar(MonthlyData2017)
title('2017 Data')
xlabel('Month')
ylabel('No. of Cyclists')

[Shiva]

Thank you for your assistance. i really do appreciate it.

[VBBV]

Sorry, @Image Analyst suggestion is correct. your input files have several missing data formats (in patches) for datetime column.

[VBBV]

I wonder why you still get the same error. It seems you are converting data to table and then back to array data. May be you need to check dimensions of variables when the data is reformatted during conversions

Answer 1

[Image Analyst]

For some reason you removed all the comments, as I'm sure were in there as all professional programmers put them in. Maybe you could add the comments back in. But it looks like you are trying to get some kind of group statistics. So for that I'd recommend not doing that loop but use one of the functions: splitapply, groupsummary, or grpstats.