# How to properly write a matrix in a for loop?

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David Mrozek on 16 Mar 2021
Commented: David Mrozek on 19 Mar 2021
Hello everyone,
I have been trying various ways to create a gcode for 3D printers. My probably last goal will be to create such a code only in MATLAB without external software being active. Hence I have written a code which should give me a total of 12 gcode unnested gcode instructions (equal to the data_test attachment of a 1 x 12 cell):
for gc = 1:12
append_1 = transpose(repelem("G1",height(Importset{1, gc})));
append_2 = transpose(repelem("F1200",height(Importset{1, gc})));
append_3 = transpose(repelem("X",height(Importset{1, gc})));
append_4 = transpose(repelem("Y",height(Importset{1, gc})));
append_5 = transpose(repelem("Z",height(Importset{1, gc})));
T3 = Importset{1, gc}(:,1);
T4 = Importset{1, gc}(:,2);
T5 = Importset{1, gc}(:,3);
g_code = [append_1 + append_3 + T3 + append_4 + T4 + append_5 + T5 + append_2]; % this gives me only one out of the inital 12 cells !!
end
The result, see the attachment file "g_code_unfinished", is just one out of the twelve cells and not the desired full twelve cells. So I would like to ask you where my mistake is?
##### 1 CommentShowHide None
David Mrozek on 16 Mar 2021
I want to achieve the same data structure (like in the g_code_unfinished attachment) for all my cells. Currently I only have one out of the 12 cells in my desired structure (because my for loop is wrong)

Aghamarsh Varanasi on 19 Mar 2021
Edited: Aghamarsh Varanasi on 19 Mar 2021
Hi David,
For the 'gcode' variable to save all the data for 12 cells of input, 'gcode' also needs to be a cell array of size 12. And the calculated value needs to be stored in the variable 'gcode'. Small tweaks to your code can help you achieve this.
% initialize g_code to be a cell array of size 1 x 12
g_code = cell(1,12);
for gc = 1:12
... % your code for calculating other variables goes here
% append the current result of this iteration of for loop to the g_code variable
g_code{gc} = [append_1 + append_3 + T3 + append_4 + T4 + append_5 + T5 + append_2];
end
You can now save the variable 'gcode' to a mat file. For more information go through the documentation pages of for loop and cell arrays.
I would also recommend you to take up the 'free' MATLAB OnRamp training. This can help you understand the basic MATLAB concepts.
##### 1 CommentShowHide None
David Mrozek on 19 Mar 2021
Ok the first line of yout code did the job.
I have tried framing the gc variable in the {} before, but it did not worked because of the missing reference. Thanks!!!

R2020b

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