Extract a single struct from a Matlab struct of arrays

Question

Suppose I'm given a struct of arrays, e.g.:

s = 

foo: [3x3 double]
bar: [3x1 double]

Is there an easy way to extract a struct with the same field names as s and with each field populated by the ixth row of the same field in s? I can assume that every field has the same number of rows. Given the above, I could do

ix = 1;
s1.foo = s.foo(ix, :);
s1.bar = s.bar(ix, :);

But if s has more than a couple fields, this gets unwieldy. Is there a function that would do the equivalent, a la s1 = extractstruct(s, ix)?

In fact, it would be sweet to have a function fieldfun

Oli
– Oli

2011-12-11 21:55:31 +00:00
Commented Dec 11, 2011 at 21:55 — Oli
– Oli, Commented Dec 11, 2011 at 21:55
@Oli, try structfun

Nzbuu
– Nzbuu

2011-12-12 00:08:47 +00:00
Commented Dec 12, 2011 at 0:08 — Nzbuu
– Nzbuu, Commented Dec 12, 2011 at 0:08

Oli · Accepted Answer · 2011-12-11 21:49:19Z

1

It s not as short as s1 = extractstruct(s, ix), but I would do that:

s.foo = rand(3);
s.bar = rand(1,3);
xi=1;

s2=reshape([fieldnames(s)'; cellfun(@(x) x(xi,:),struct2cell(s)','UniformOutput',0)],1,[]);
s2=struct(s2{:})


s2 = 

    foo: [0.8147 0.9134 0.2785]
    bar: [0.7922 0.9595 0.6557]

edited Dec 11, 2011 at 21:49

answered Dec 11, 2011 at 21:40

Oli

16.1k7 gold badges54 silver badges67 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

dantswain Over a year ago

Should 'Un)],1,[]iformOutput' be 'UniformOutput'?

dantswain Over a year ago

Also, to be exactly my problem, it should be s.bar = rand(3,1) so that it has the same number of rows. /nitpicky

Nzbuu Over a year ago

This would be better with cell2struct rather than struct.

Collectives™ on Stack Overflow

Extract a single struct from a Matlab struct of arrays

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related