Undefined function or variable 'isnan'
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Carver Nabb
am 7 Jan. 2019
Kommentiert: Walter Roberson
am 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 Kommentare
nanren888
am 7 Jan. 2019
As Walter says; It is complaining about the two-parameter isnan(x,y) that you've invented :)
Akzeptierte Antwort
Walter Roberson
am 7 Jan. 2019
You have
pairs = pairs(~isnan(pairs(:,2),:));
You want
pairs = pairs(~isnan(pairs(:,2)),:);
21 Kommentare
Weitere Antworten (2)
Jan
am 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 Kommentare
Kholoud Alzoubi
am 19 Apr. 2021
Undefined function or variable 'textdata'.
Error in KopackRFNNGOA (line 15)
x1=textdata(~isnan(textdata)); %temperature
1 Kommentar
Walter Roberson
am 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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