# Stacking data sets into 1

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Jason on 26 Jan 2018
Commented: Star Strider on 26 Jan 2018
I am trying to stack data. I have an matrix (ROI), that I obtain the rows from. Each row is my y data. The x data is just the column number (1:num_of_columns)
for each row of data, I need to take the column number and shift it by an amount in a vector called thresh (and column2).
I then want to combine each set of data. The left graph shows the first 2 rows i plot seperately before the x-axis shift. The right hand graph is individual plots of all the rows each shifted (from the vector thresh(:,2)). stack=[];
for i=1:num_of_rows
y=ROI(i,:);
plot(x-thresh(i,2),y,'r.'); hold on;
if i==1
stack(:,1)=x-thresh(i,2);
stack(:,2)=y;
else
stack(:,1)=vertcat(stack(:,1),x-thresh(i,2))
stack(:,2)=vertcat(stack(:,2),y)
end
end
grid on;
stack
Error using vertcat
Dimensions of matrices being concatenated are not consistent.
Error in ArchimedesIQC>pushbutton126_Callback (line 12236)
stack(:,1)=vertcat(stack(:,1),x-thresh(i,2))

Star Strider on 26 Jan 2018
What are the row and column sizes of ‘x’ and ‘y’?
Since ‘thresh’ appears to be a scalar in each iteration, it is likely not the problem.
Guillaume on 26 Jan 2018
No, the problem is
x(:, 1) = [x(:,1), something_not_empty]
the number of elements on the left hand side is always going to be smaller than the number of elements on the right hand side. This is always going to result in an error in matlab.
The error itself may be caused by x being a row vector instead of a column vector.
Star Strider on 26 Jan 2018
‘The error itself may be caused by x being a row vector instead of a column vector.’
Precisely the reason I asked for their dimensions before proceeding!

Guillaume on 26 Jan 2018
Edited: Guillaume on 26 Jan 2018
I have not really understood what it is you're trying to achieve but fixing your error is easy:
else
stack = [stack; x-thresh(i, 2), y]; %or vertcat(stack, [x-thresh(i, 2), y]);
end
Note that this assumes that x and y are column vectors. If they are row vectors, you need to transpose them:
stack = [stack; x.' - thresh(i, 2), y.'];