How to Ignore NaN values when plotting?
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Hi, If anyone can tell me how to ignore NaN values when you are plotting? Thanks
2 Comments
Rik
on 27 Jul 2019
What do you mean? Most plotting functions will already ignore NaN values by default.
dpb
on 27 Jul 2019
+1
Altho there are two ways to consider what the Q? might mean and how the plot might look...consider the following:
y=[1:3 nan 4:7]; % data array w/ an included NaN
subplot(2,1,1)
plot(y,'*-')
legend('NaN silently ignored','Location','northwest')
subplot(2,1,2)
plot(y(isfinite(y)),'*-')
legend('NaN removed from dataset','Location','northwest')
which produces:

So, "how" depends upon what effect one is after -- the straightforward way plot() just leaves holes where NaN elements reside--if one doesn't include them by exclusion programmatically, then the resulting plot makes look like they don't exist at all..which may or may not be kosher in displaying the data.
"It all depends!" :)
Answers (2)
Juan Carlos Ortega
on 13 Jun 2023
Inthis case, not work:
y=[1 3 nan 4 7]; % data array w/ an included NaN
x=[2 3 5 7 9];
subplot(2,1,1)
plot(x,y,'*-')
legend('NaN silently ignored','Location','northwest')
subplot(2,1,2)
plot(x,y(isfinite(y)),'*-')
legend('NaN removed from dataset','Location','northwest')
1 Comment
Les Beckham
on 13 Jun 2023
Edited: Les Beckham
on 13 Jun 2023
y=[1 3 nan 4 7]; % data array w/ an included NaN
x=[2 3 5 7 9];
subplot(2,1,1)
plot(x,y,'*-')
legend('NaN silently ignored','Location','northwest')
subplot(2,1,2)
plot(x(isfinite(y)),y(isfinite(y)),'*-') % use the same indexing for both x & y
legend('NaN removed from dataset','Location','northwest')
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