For consistency with "nan", wouldn't it be nice to be able to issue "missing(3)"?

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<Missing> is the string counterpart to NaN. One can define a (say) 3x3 array of NaN's. Each NaN can be replaced as the data is generated in the analysis process, which is handy if the data isn't generated simultaneously. At no point is there any confusion between NaN versus a valid zero datum.
It would be nice to be able to do this for strings. Of course, one can issue "string(nan(3))" or "repmat(missing,3,3)". But as code gets more intricate, simplicity becomes more valuable.
  11 Comments
FM
FM on 27 Apr 2022
@Jan: In 2019a, missing(2,3) and missing(2,3,'string') are not recognized. I'm still waiting to upgrade. The command "doc missing" yields a very sparse documentation page....
Jan
Jan on 27 Apr 2022
@FM: In R2022a this syntax is not working also - you can try this here in the forum's interpreter:
missing(2,3,'string')
Error using missing
Too many input arguments.
So this is a useful enhancement request. Please use the link on the bottom of this page to contact the MathWorks team and suggest this improvement.

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Answers (1)

Bruno Luong
Bruno Luong on 27 Apr 2022
Why not define your own function
mymissing
ans = missing
<missing>
mymissing(3)
ans = 3×3 missing array
<missing> <missing> <missing> <missing> <missing> <missing> <missing> <missing> <missing>
mymissing(2,3)
ans = 2×3 missing array
<missing> <missing> <missing> <missing> <missing> <missing>
mymissing(2,'string')
ans = 2×2 string array
<missing> <missing> <missing> <missing>
mymissing(2,3,'double')
ans = 2×3
NaN NaN NaN NaN NaN NaN
function x = mymissing(varargin)
% x = mymissing(size)
% x = mymissing(n1, n2, ...)
% x = mymissing(..., class)
x = missing;
if ~isempty(varargin)
if ischar(varargin{end}) || isstring(varargin{end})
sz = [varargin{1:end-1}];
if isempty(sz)
sz = 1;
end
cls = varargin{end};
x = repmat(feval(cls,x), sz);
else
sz = [varargin{1:end}];
x = repmat(x, sz);
end
end
end
  12 Comments
FM
FM on 27 Apr 2022
@Bruno Luong: No, I should have been clearer. the 2019a documentation for "missing" does not describe it a specific to "string". I got that from the page cited in my last reply. Which is a very specific page for strings and missing values.

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