UNEMPTY

Sets empty fields in a structure to a defined value.

Description

This function is useful if numeric values from a structure array are to be extracted using the notion M = S.field] UNEMPTY makes sure that empty matrices in the structure do not affect the size of M.
 
S = unempty(C) sets all occurences of empty matrices in all fields of C to NaN.
 
[S,nc] = unempty(C) reports the number of changed fields in nc.
 
S=unempty(C,F) sets in a structure array all occurences of empty matrices for field F to NaN.

S=unempty(C,F,value) sets all occurences of empty fields to value.
 
Example:

S=[struct('f',1) struct('f',2) struct('f',[]) ];
disp([S.f]) % size is different from S
   1 2
S = unempty(S);
disp([S.f]) % size is the same as S
   1 2 NaN

• MATLAB release: MATLAB 6.1 (R12.1)

[Jos x@y.z]

More effective:
% the data
S=[struct('f',1) struct('f',2) struct('f',[]) ];
% insert NaNs
[X{1:length(S)}] = deal(S.f) ;
X{cellfun('isempty',X)} = NaN ;
% the result
SS = [X{:}] ;