writing a vector using "readTrajectory" function in Dymola - dymola

Question

I write a vector in Dymola mos script in a simple manner like this:
x_axis = cell.spatialSummary.x_cell;
output: x_axis={1,2,3,4,5} // row vector
I want to do the same thing in a function.'x_cell' has 5 values which I want to store in a row vector. I use DymolaCommands.Trajectories.readTrajectory function to read x_cell values one by one in for loop (I use for loop because, readTrajectory throws an error when I try to read entire x_cell)
Real x_axis[:],axis_value[:,:];
Integer len=5;
for i in 1:len loop
axis_value:=readTrajectory(result,{"cell.spatialSummary.x_cell["+String(i)+"]"},1); //This intermediate variable returns [1,1] matrix
x_axis[i]:=scalar(axis_value);
end for;
I get an error:
Assignment failed x_axis[i] = scalar(axis_value);
what's wrong here? All I want to do is read all values of x_cell and write it into a vector. How can I do this in dymola function?
Thank you!

Answer 1

Solution: Initialize the vector with a certain value. In this case,
x_axis :=fill(0, len);
This solved the above problem for me.

Answer 2

Pre filling as in the other solution works, and is generally the best solution. However, in some cases you might have to append to the vector as follows:
x_axis=fill(0.0, 0);
for i in 1:len loop
axis_value:=readTrajectory(result,{"cell.spatialSummary.x_cell["+String(i)+"]"},1); //This intermediate variable returns [1,1] matrix
x_axis:=cat(1, x_axis, {scalar(axis_value)});
end for;
(This takes x_axis and concatenates a new element at the end. It is generally slower.)