Puting empty value in numeric array

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Easy question for advanced users, big question for a beginner like me.
I want to put an empty value or no value into a numeric matrix.
As an example;
if true
for n=1:4;
If %some condition is satisfied%
Data(n,1)= % a numeric value like 4%
Else
Data(n,1)= % put nothing in this row %
end
End
end
Something like this,
Data(1,1)=3
Data(2,1)=4
Data(3,1)= no value,it exist but no value in it
Data(4,1)=5

Accepted Answer

meghannmarie
meghannmarie on 9 Oct 2019
How about putting a NaN in it?
Data(n,1)= NaN;
  5 Comments
Ugur Acar
Ugur Acar on 9 Oct 2019
Thank you John for 'omitnan'. Can u suggest any solution about calculating the values of NaN elements in the data matrix using interpolate function
Turlough Hughes
Turlough Hughes on 9 Oct 2019
You could sum the data in your array by excluding NaNs during summation:
sum(Data(~isnan(Data)))

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More Answers (1)

Ugur Acar
Ugur Acar on 9 Oct 2019
you are right, i couldnt put nothing in a array. as i said, in the first step i want to determine empty elements in the array according to my if statement, then i will try to find these values with the help of other known elements using interpolate function.
  4 Comments
meghannmarie
meghannmarie on 9 Oct 2019
Edited: meghannmarie on 9 Oct 2019
When you use sum or any other statistics use the nan flag if you do not want those considered:
S = sum(Data, 'omitnan')
if you want to interpolate at the nan values, you can get of an index to all the nan values by using isnan and using interp1:
nan_idx = isnan(Data);
x = 1:numel(Data);
Data(nan_idx) = interp1(x(~nan_idx), Data(~nan_idx),x(nan_idx));
Ugur Acar
Ugur Acar on 9 Oct 2019
Nan flag will solve the problem i believe thanks meghannmarie

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