Find minimum value within struct

Hi

I'm trying to determine the minimum value within a struct. I have a data struct with subfields which are timestamped. I'd like to find the smallest time, then reference all the other data accordingly.

example of the data:

• data.val1.time = something
• data.val2.time = something else
• .
• .
• data.valN.time = something else

I can think of a brute force way of doing it, but I'm thinking that there should be a nicer way.

anyone have any ideas?

[Jan]

Are "val1", "val2", ... the real field names? Then I strongly recommend to use an array instead: val(1), val(2), ... This will make the conversion of the subfield .time much easier.

Answer 1

[Friedrich]

Hi,

I think you have to convert from a structure to an array. Maybe like this:

>> data.a = 1;
>> data.b = 2;
>> data.c = 3;
>> min(cell2mat(struct2cell(data)))

[Friedrich]

for your struct more ugly:

min(cell2mat(struct2cell(cell2mat(struct2cell(data)))))

[Jan]

I assume this is faster:

C = struct2cell(data);

min([C{:}])

Answer 2

[Sean de Wolski]

min(structfun(@min,data));

is significantly faster on my machine. Conversions to and from cells take awhile.

[Jan]

STRUCT2CELL is surprisingly fast, because the underlying representation is almost equivalent: Only the list of field names is different.

But CELL2MAT is slow, because it does not pre-allocate sufficiently. Anyhow, for 3 or 100 fields the speed will not be too important.