How to Fix "Warning: Colon operands must be real scalars" Warning

1,446 次查看（过去 30 天）
B. Burak
B. Burak 2024-4-7
评论： Voss 2024-11-7，23:31
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)
  3 个评论
显示 1更早的评论
B. Burak
B. Burak 2024-4-8
I tried this like "ply_%d" for the sheet name. It does not work either.
Michael Toledano
Michael Toledano 2024-7-31
I'm getting the same error for an all-alpha-character command. Is there any fix or workaround available?

请先登录，再进行评论。

请先登录，再回答此问题。

回答（7 个）

Jakob Weis
Jakob Weis 2024-4-23
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.
Ryan Lamb
Ryan Lamb 2024-6-12
编辑：Ryan Lamb 2024-6-12
I think the Warning is coming from the 'WriteMode' being set to 'Append'.
I get the same warning any time I append to a row greater than 10.
  3 个评论
显示 1更早的评论
Voss
Voss 2024-11-7，23:31
Ran in:
"... extracts all digits between 0 and 9 in the variable endCol into the vector startNumInRow"
That regexp call is not extracting the digits, just recording their locations:
endCol = 'Q102';
startNumInRow = regexp(endCol,'[0-9]')
startNumInRow = 1×3
2 3 4
<mw-icon class=""></mw-icon>
<mw-icon class=""></mw-icon>

请先登录，再进行评论。

VBBV
VBBV 2024-4-7
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 个评论
显示 7更早的评论
VBBV
VBBV 2024-4-8
Ran in:
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)
sheet_name = "ply_case_4"
B. Burak
B. Burak 2024-4-8
编辑：B. Burak 2024-4-8
Yes, "design-case" is an existing folder in the current folder along with the file I run so backward slash use in designating relative file path gives me an error. Also I tried the alternative sheet name scheme as you and the other user pointed out, and still get the same warning. Additionally, it is worth mentioning something I noticed in the created case.xlsx file when I look over it. I attach a related image of it below. After some column it does not write in values as expected.

请先登录，再进行评论。

Steven Lord
Steven Lord 2024-4-9
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);
  1 个评论
B. Burak
B. Burak 2024-4-9
I edited said .m file for minimally reproducible example of the warning, and you can find it appended to this message. I hope this helps.

请先登录，再进行评论。

Nieves
Nieves 2024-7-25
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.
Will Reeves
Will Reeves 2024-9-17
编辑：Will Reeves 2024-9-17
Ok, not an actual answer, but I'm certain that it's Mathworks' mistake that they have to address (before a "future release" at least.)
I tried @Ryan Lamb's suggestion and wrote 10 lines (one line at a time) using append. Adding the 10th line caused the warning:
I'll raise it as a support request as it's pretty irratating.
Meik Gawron
Meik Gawron 2024-9-29
Hi,
I had this error message too.
I have to work loop-wise on 3 variables (assembled in an array of coloums) of case varying common lengthes.
The problem was:
-> To identify the actual length I used "size(array)" which produces a two-dimensional vector [n m], and that certainly is problematic to derive the number of loops necessary. (Un?)Fortunately Matlab 2024 was smart to anticipate what I was heading for, however producing the error meassge.
Finally I replaced "size(x)" by "length(x)" and the error message disappeared now...
BR
Meik

标签

产品


版本

R2024a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by