Selecting/counting NaN elements

I have a cell array where some values are NaN. The rest of the elements are characters. I want to count the NaN elements in addition to the characters, that I already have in place. Of course, it's not counting NaN values. I can turn NaN into characters or zeroes (the other elements are not numerical so the value wouldn't matter). However, if I try

isnan(A{a,b})

I get the error Undefined function 'isnan' for input arguments of type 'cell'.

[Stephen23]

@Jasmine Karim: it looks like you have multiply nested cell arrays. Please upload that variable in a .mat file, by clicking the paperclip button.

[Jasmine Karim]

I edited my original question because I think it was incorrectly worded. I have a matrix that holds 6 matrices. In each of those matrices is a basic output that looks like A (attached here).

Answer 1

[Stephen23]

"I have a cell array where some values are NaN."

True. There are four NaN's in your cell array:

>> idx = cellfun(@(v)isnumeric(v)&&any(isnan(v)),A);
>> nnz(idx)
ans =  4
>> find(idx)
ans =
   67
   69
   80
   98

"The rest of the elements are characters"

False. In fact most of the cells contain numeric data:

>> numel(A)
ans =  132
>> nnz(cellfun(@isnumeric,A))
ans =  70
>> nnz(cellfun(@ischar,A))
ans =  62

Well, in any case, I showed you how to count the NaN's, as your question requested.

[Jasmine Karim]

Thank you.

I wasn't clear, I meant that in the 3rd column, the rest of the elements are characters. Can I change the ones (in the 3rd column) that are NaN to characters as well?

The reason being that later on I filter the data in this matrix based on the 'yes' 'no' and the NaN responses actually signify an incorrect response.

[Stephen23]

@Jasmine Karim: you can easily detect NaN values in the third column:

fun = @(v)isnumeric(v)&&isscalar(v)&&isnan(v);
idx = cellfun(fun,A(:,3))
A(idx,3) = {'hello world'}

If you only expect scalar NaN, then you might be able to simplify this to:

idx = cellfun(@isnan,A(:,3))

Experiment and see what works for your situation.