# ignore NaN value in the matris

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Ali Topal am 3 Nov. 2023
Beantwortet: Jeremy Hughes am 4 Jan. 2024
I want to ignore NaN values in my matrix. But I don't want it to sum or average the matrix. I just want it to operate with existing values, ignoring values that NaN in the matrix. Can you help me?
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Dyuman Joshi am 3 Nov. 2023
Bearbeitet: Dyuman Joshi am 7 Nov. 2023
@Ali Topal, What error(s) do you get with NaN values?
Rik am 18 Dez. 2023
If you explain what exactly you want to do, we might be able to suggest a solution. The constraints you describe make a solution impossible, so any solution will require breaking one of your requirements (but that might not actually be a problem).

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### Antworten (1)

Jeremy Hughes am 4 Jan. 2024
There are a few ways to do this. Let's make an example vector with NaNs
x = rand(1,10);
x(1:4:end) = NaN
x = 1×10
NaN 0.7982 0.4286 0.0077 NaN 0.0374 0.5173 0.7096 NaN 0.2903
Now, for SUM, you probably just want to omit the NaNs using logical indexing.
x(~isnan(x)) % Returns only the non-NaN values
ans = 1×7
0.7982 0.4286 0.0077 0.0374 0.5173 0.7096 0.2903
sum(x(~isnan(x)))
ans = 2.7891
Or, you can use the nanflag parameter: nanflag
sum(x,"omitnan")
ans = 2.7891
Not every function has an "omitnan" flag, so the first example would work when that's not the case.
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