MATLAB: Error using Bar, X must be same Length as Y.

bartableuiaxes

I am trying to plot on a bar chart through app designer and i'm getting the following error: Error using bar (line 172)
X must be same length as Y.
My code is as below:
bar(app.UIAxesPositionBar, T_BarChart.UndlyDate, T_BarChart{:,{'TotalPosition'}}, 0.8,'FaceAlpha',0.5);
hold(app.UIAxesPositionBar,'on');
bar(app.UIAxesPositionBar, T_BarChart.UndlyDate, T_BarChart{:,{'FuturesPosition','DeltaEquivPosition'}}, 0.8,'FaceAlpha', 0.5);
The second call to bar throws the error, when i inspect the table i'm using you can see its 1×4, the first call to bar works just fine.
You can see the table contents/variables below:
K>> bar(app.UIAxesPositionBar, T_BarChart.UndlyDate, T_BarChart{:,{'FuturesPosition','DeltaEquivPosition'}}, 0.8,'FaceAlpha', 0.5);
Error using bar (line 172)
X must be same length as Y. 
K>> T_BarChart.UndlyDate
ans =
datetime
01-Dec-2019
K>> T_BarChart{:,{'FuturesPosition','DeltaEquivPosition'}}
ans =
1.0e+02 *
0 -1.887165000000000
K>> T_BarChart
T_BarChart =
1×4 table
UndlyDate FuturesPosition DeltaEquivPosition TotalPosition
___________ _______________ __________________ _____________
01-Dec-2019 0 -188.7165 -188.7165
Any ideas on why i am getting the "must be the same length" error?

Best Answer

As the error indicates, x and y must be the same length. Here's a demo to understand the error:
bar(1,2)       % this is OK
bar([1,2,3],[1 1 1;2 2 2]) % this is also OK because
% length([1,2,3]) = 3 and length([1 1 1;2 2 2]) = 3
bar(1,[1,2])   % this produces an error
Error using bar (line 172)
X must be same length as Y.
One solution is to specify two x values
bar([1,2], [4,5])
Another solution is to not specify the x values at all. It looks like one column is a single value while the other column might be two stacked values. In that case you can do something like this:
bar([0 5; 2 3],'stacked')
Read more about inputting matrices in bar(): https://www.mathworks.com/help/matlab/ref/bar.html
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