# How to identify the position in which a value is NaN

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Alfredo Scigliani on 20 Apr 2022
Commented: Voss on 20 Apr 2022
I want to be able to identify the position in which a value is NaN
If I have:
x = [1 NaN 3 4 5 NaN 7 8 9 10]
In which the second and sixt position are NaN
something that gives me an answer = [ 2 , 6 ] is what I am looking for.
I usually use the "find" such as find(x==3) would return = 3 (because it is at the third position), but now I want to apply it for NaN
Not sure how that could be done, wonder if anybody can help me. Thanks in advance!

Voss on 20 Apr 2022
Edited: Voss on 20 Apr 2022
You can use the isnan function:
x = [1 NaN 3 4 5 NaN 7 8 9 10];
find(isnan(x))
ans = 1×2
2 6
##### 2 CommentsShowHide 1 older comment
Voss on 20 Apr 2022
You're welcome!

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