Undefined function or variable 'isnan'
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Carver Nabb
on 7 Jan 2019
Commented: Walter Roberson
on 19 Apr 2021
I am met with the error "Undefined function or variable 'isnan'" when running this code:
%counter = 1:4
%a is a 220x4 cell
%data is a 220x4 double
for i = size(a, 1)
pairs = [];
pairs(:,1) = counter;
pairs(:,2) = data(i,:);
pairs = pairs(~isnan(pairs(:,2),:));
slope(i) = polyfit(pairs(:,1),pairs(:,2),1);
end
I can't seem to figure out exactly why. Is the way I'm using the NOT operator?
3 Comments
nanren888
on 7 Jan 2019
As Walter says; It is complaining about the two-parameter isnan(x,y) that you've invented :)
Accepted Answer
Walter Roberson
on 7 Jan 2019
You have
pairs = pairs(~isnan(pairs(:,2),:));
You want
pairs = pairs(~isnan(pairs(:,2)),:);
21 Comments
More Answers (2)
Jan
on 7 Jan 2019
Although I assume that Walter hit the point already, I suggest to use teh debugger to identify such problems. Type in the command window:
dbstop if error
Now run the code again until it stops. Check the currently processed line by evaluating it piecewise:
% pairs = pairs(~isnan(pairs(:,2),:))
pairs(:,2)
~isnan(pairs(:,2),:) % <- This should fail already
pairs(~isnan(pairs(:,2),:))
As Walter has said already, isnan(x, :) is meaningful only, if it is an array. Otehrwise using the colon as second input is not valid, if the function isnan() is meant. The error message "Undefined function or variable 'isnan'" is not really clear here. But splitting the commands into parts using the debugger helps to understand the problem.
0 Comments
Kholoud Alzoubi
on 19 Apr 2021
Undefined function or variable 'textdata'.
Error in KopackRFNNGOA (line 15)
x1=textdata(~isnan(textdata)); %temperature
1 Comment
Walter Roberson
on 19 Apr 2021
Not enough context.
You are trying to use a variable named textdata that has not been assigned to.
Also, the variable name would tend to suggest that the variable is not expected to hold numeric data, so isnan() is questionable here.
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