Octave/MATLAB: How to compare structs for equality?

Question

How do I compare two structs for equality in octave (or matlab)?

Attempting to use the == operator yields:

binary operator `==' not implemented for `scalar struct' by `scalar struct' operations

Answer 1

Use either the isequal or isequalwithequalnans function. Example code:

s1.field1 = [1 2 3];
s1.field2 = {2,3,4,{5,6}};
s2 = s1;
isequal(s1,s2)  %Returns true (structures match)

s1.field3 = [1 2 nan];
s2.field3 = [1 2 nan];
isequal(s1, s2)              %Returns false (NaN ~= NaN)
isequalwithequalnans(s1, s2) %Returns true  (NaN == NaN)

s2.field2{end+1}=7;
isequal(s1,s2)               %Returns false (different structures)

isequal(s1, 'Some string')   %Returns false (different classes)

Answer 2

I would just write a function isStructEqual(struct1,struct2) that performs regular comparisons on all of the member attributes. If any such comparison returns 'false' or '0', then immediately exit and return 'false', otherwise if it makes it all the way through the list of member attributes without that happening, return true. If the struct is extremely large, there are ways to automate the process of iterating over the member fields.

Looking on the central file exchange, you might try this file.