Why do I receive this error while using a MATLAB help example?

I am trying to do something similar to this MATLAB example that is provided in Help:

syms x y z
S = struct('f1',x*y,'f2',y + z,'f3',y^2)

S = struct with fields:
    f1: x*y
    f2: y + z
    f3: y^2

Sval = subs(S,[x y z],[0.5 1 1.5])

Sval = struct with fields:
    f1: 1/2
    f2: 5/2
    f3: 1

but I get this error:

"Error using subs

Expected input number 1, S, to be one of these types:

sym

Instead its type was struct.

Error in sym/subs (line 60)

validateattributes(F, {'sym'}, {}, 'subs', 'S', 1);"

What went wrong?

[Torsten]

Seems your MATLAB version is an old one (see above).

[Sara Nikdel]

I updated my MATLAB and it works now, thank you.

Answer 1

[Michael]

This ran fine on my machine. See below. What version of Matlab are you using? Maybe an older version that doesn't support struct inputs?

 syms x y z
S = struct('f1',x*y,'f2',y + z,'f3',y^2)

S = struct with fields:
    f1: x*y
    f2: y + z
    f3: y^2

Sval = subs(S,[x y z],[0.5 1 1.5])

Sval = struct with fields:
    f1: 1/2
    f2: 5/2
    f3: 1

[Michael]

Symbolic matrix inputs were just supported in verions 2021b.It doesn't mention struct inputs.