# Finding length of a struct, excluding NaN values

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Manny Kins on 8 Jul 2019
Edited: Stephen23 on 8 Jul 2019
I have a struct with the following layout:
T X Y
[0,1] [0, 1] [0,5]
[0] [2] [2]
NaN NaN NaN
NaN NaN NaN
NaN NaN NaN
NaN NaN NaN
I want to find the length of the struct excluding the trailing NaN values at the bottom. So in this case the length would be 2 instead of 6.
I have attached a file with some of the values that I am using and the struct shape. Thanks

Stephen23 on 8 Jul 2019
Edited: Stephen23 on 8 Jul 2019
You can do this very easily with the accepted answer to your very similar question from two months ago:
Just use the logical variable X:
>> F = @(s)all(structfun(@(a)isscalar(a)&&isnan(a),s)); % or ANY
>> X = arrayfun(F,AllData.Passive)
X =
0 0 0 0 1 1 1 1 1 1 1 0 0 0 0
>> nnz(~X)
ans = 8
Manny Kins on 8 Jul 2019
Hi Stephen, yes sorry your answer does indeed give the length of a struct without including any NaN values. I was just mentioning that for me when the struct becomes quite large (lengths of around 1000000) the code:
X = arrayfun(F,AllData.Passive)
becomes very slow. I have tried a workaround
if isnan(AllData.Passive(j).PX)
break
end
which just breaks out of the loop when it comes across a NaN value.
This seems to work much faster.
Your suggestion is however much more universal in that it can be applied to structs where there are NaN values scattered around the struct and do not only form below the useful data.
Thanks
Stephen23 on 8 Jul 2019
Edited: Stephen23 on 8 Jul 2019
@Manny Kins: a well-designed loop will most likely be faster than arrayfun.

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