'Value' must be double scalar within the range of 'Limits'

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Lola 2022-6-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1741985-value-must-be-double-scalar-within-the-range-of-limits

评论： Adam Danz 2022-6-16

tests1.csv

Hi. I am creating a gui on appdesigner. I am reading numeric data from a csv file and storing this data in an array. I want to calculate the standard deviation of the values store in the array and display it on the numeric edit field. The error I get is 'Value' must be a double scalar within the range of 'Limits'. But my Limit of the editfield is -Inf,Inf. The csv file is attached and the code is provided below. Please assist.

data=readtable('tests1.csv','NumHeaderLines',9);
col_vec=data{:,2}
app.stdEditField.Value=std(col_vec);

I tried editing the code to :

app.stdEditField.Value=std(single(col_vec))

Or

app.stdEditField.Value=std(double(col_vec))

But the error still pops up.

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Adam Danz 2022-6-16

Please show us the results of data{:,2}, a few rows will be sufficient.

It may be helpful to see the results of std(col_vec) as well.

If col_vec is not a vector, then the result of std will not be a scalar. Table columns can contain matrices, for example.

Another possibility is that std is returning a NaN or Inf which may not pass the UI component validation.

Lola 2022-6-16

Hi. I have attached the csv file that has the results in it. It is column 2. I'm reading the values after 9 rows

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Answer 1

Adam Danz 2022-6-16

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1741985-value-must-be-double-scalar-within-the-range-of-limits#answer_987240

编辑：Adam Danz 2022-6-16

在 MATLAB Online 中打开

tests1.csv

Your data contains a NaN value.

data=readtable('tests1.csv','NumHeaderLines',9);
col_vec=data{:,2};
n = sum(isnan(col_vec)); 
fprintf('There are %d NaN values in col_vec\n', n)
There are 1 NaN values in col_vec
std(col_vec)
ans = NaN

Where is the NaN value?

nanLoc = find(isnan(col_vec)); 
fprintf('NaN in row %d', nanLoc)
NaN in row 789

When there is at least 1 NaN in a vector, std will return NaN.

Options:

Figure out why there are NaNs and replace them (manually, smoothing, interpolation, etc)
Ignore the NaNs: S = std(___,nanflag)

sd = std(col_vec,'omitnan')
sd = 37.5436

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Lola 2022-6-16

编辑：Lola 2022-6-16

Thank you so much ! I have tried the last line of code a few minutes ago and it did work but I didn't understand where the NaN value was and how to find it. Thank you for your help. It is much appreciated