Comma separated list generation

How can you expand a comma separated list from a repetition? I am searching for the elegant way to do something like this:

Instead of

Y = blkdiag(X, X, X),

write Y = repblkdiag(X,3). The code I use now is:

function Y = repblkdiag(X, n)
Y = [];
for j = 1:n
    Y = blkdiag(Y, X);
end

I expected that something like

Y = blkdiag(deal(repmat(X,3)))

would work. Thanks for your interest and contribution,

Jan

Answer 1

[Andrei Bobrov]

xc = repmat({X},1,3)
Y = blkdiag(xc{:})

[Jan]

Thanks Andrei,

This is indeed more elegant. No possibility to do it in-line?

Regards,

Jan

[Andrei Bobrov]

I think don't possible

[Teja Muppirala]

It is possible to do it in one line, but I think Andrei's solution is simpler.

Y = eval(['blkdiag( ' repmat('X,',1,3) '[])'])

[Stephen23]

Another neat approach:

C = {X};
Y = blkdiag(C{[1,1,1]})

One line (since R2019b):

Y = blkdiag(struct('x',repmat({X},1,3)).x)

... but I recommend using two lines.