How to Fix "Warning: Colon operands must be real scalars" Warning
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When I run the code below, it works as I wanted, but I get a warning. I tried different things to fix it, but of no avail. How can I refactor my code so that I will not face any related issue as the warning states if I can?
ply_nums_range = [4, 8, 16, 32, 64];
x = rand(1, 2);
data = cartesian_product({b_range, ...
N_xx_range, ...
N_yy_range, ...
N_xy_range, ...
ang_range});
for e = ply_nums_range
ply_nums = e;
for i = 1:length(data)
b = data(i, 1);
N_xx = data(i, 2);
N_yy = data(i, 3);
N_xy = data(i, 4);
ang = data(i, 5);
iteration = [a, ...
b, ...
N_xx, ...
N_yy, ...
N_xy, ...
[PLY_ANGS(ang, x), flip(PLY_ANGS(ang, x))]];
thetas = cell(1, ply_nums);
for j = 1:ply_nums
thetas{j} = sprintf("theta_%d", j);
end
variable_names = ["a", "b", "N_xx", "N_yy", "N_xy", thetas];
table_data = array2table(iteration, ...
'VariableNames', ...
variable_names);
sheet_name = sprintf("%d_ply_case", e);
writetable(table_data, ...
"design-cases/case.xlsx", ...
'WriteMode', 'Append', ...
'Sheet', sheet_name);
end
end
Console output:
Warning: Colon operands must be real scalars. This warning will become an error in a future release.
> In matlab.io.spreadsheet.internal.write.writeXLSFile>getRangeToWrite (line 575)
In matlab.io.spreadsheet.internal.write.writeXLSFile (line 262)
In writetable (line 426)
In test_case (line 72)
2 Comments
Walter Roberson
on 7 Apr 2024
there is something odd about the way it is interpreting the sheet parameter. Please verify that sheet_name contains a valid character vector. Experiment with moving the numeric part of the character vector to the end.
Answers (5)
Jakob Weis
on 23 Apr 2024
In my case the warning was triggered because the colon operands were indexed with for-loop indices which I accidentally parsed as a column rather than a row vector.
for_indices = (1:10)'; % Column vector parsed as for-indices triggers warning.
X = 1:10;
Y = 101:110;
for i = for_indices
R = X(i):Y(1);
end
It doesn't look like this is the issue OP is facing but I thought I'd mention it in case somebody else comes across this thread.
0 Comments
VBBV
on 7 Apr 2024
for k = 1:numel(ply_nums_range)
ply_nums = ply_nums_range(k); %
for i = 1:length(data)
b = data(i, 1);
N_xx = data(i, 2);
N_yy = data(i, 3);
N_xy = data(i, 4);
ang = data(i, 5);
iteration = [a, ...
b, ...
N_xx, ...
N_yy, ...
N_xy, ...
[PLY_ANGS(ang, x), flip(PLY_ANGS(ang, x))]];
thetas = cell(1, ply_nums);
for j = 1:ply_nums % scalar limit
thetas{j} = sprintf("theta_%d", j);
end
variable_names = ["a", "b", "N_xx", "N_yy", "N_xy", thetas];
table_data = array2table(iteration, ...
'VariableNames', ...
variable_names);
sheet_name = sprintf("%d_ply_case", ply_nums);
writetable(table_data, ...
"design-cases/case.xlsx", ...
'WriteMode', 'Append', ...
'Sheet', sheet_name);
end
end
9 Comments
VBBV
on 8 Apr 2024
Though sheetname has no issues, but it may also be the cause, try to give sheetname that begins with character instead of number
sheet_name = sprintf("ply_case_%d", 4)
Steven Lord
on 9 Apr 2024
If you have a small case with which you can reproduce this behavior, could you please send it to Technical Support directly using this link? Or could you attach to this Answers post (or send it to Support) a small MAT-file with a representative table_data table array that reproduces this behavior when you run this writetable command? I'd like for us to investigate why writetable is issuing this warning message.
writetable(table_data, ...
"design-cases/case.xlsx", ...
'WriteMode', 'Append', ...
'Sheet', sheet_name);
Nieves
on 25 Jul 2024 at 4:20
I'm getting this same error, with both writetable and writematrix. My sheet names have no digits:
writetable(toWrite,fullfile(outDir,specName),'Sheet','Spectral_Data','WriteMode','Append')
writematrix(nemList,fullfile(outDir,specName1),'Sheet','FileNames','WriteMode','Append')
This error has only appeared since updating to R2024a.
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