Re: Arrays of structures

[Andrew Janke]

On 12/31/19 10:59 AM, Windhorn, Allen E [ACIM/LSA/MKT] wrote:
> Supposing I have an array of structures X, where each element of the array
> has fields .th and .r.  I can refer to a particular field like "X(3).r" if I 
> want to
> know its value, but is there a way to refer to ALL the r fields in the array 
> as
> a group, like "X(:).r"?  This just gets me the value of the r field of the 
> first
> element of the array for some reason:
>
>>> X(1).th = 23;
>>> X(1).r = 10.3;
>>> X(2).th = 17;
>>> X(2).r = 6.6;
>>> X(3).th = 47;
>>> X(3).r = 11.5;
>>> X(:).r  % (or X.r)
> ans =  10.300
> ans =  6.6000
> ans =  11.500
>>> % This shows me all the values, but...
>>> foo = X(:).r
> foo =  10.300  % Assignment only gets me the first one.  I expected:
>>> foo
> foo =
>
>    10.3000    6.6000   11.5000
>
> Using a loop is the obvious option, but I am just wondering if there is a 
> better
> way, or a better construct.
>
> Thanks for any advice you can give me.
>
> Regards,
> Allen
Hi Allen,

Dot-referencing into a nonscalar struct array gives you a
"comma-separated list" as a result. This is like a function with
multiple outputs. Which is why you see multiple "ans = " labels in the
output. So you need to either capture them to multiple variables, or
grab them all using concatenation with [...] or cellification with {...}.

>> foo = [X.r]
foo =
   1.030000000000000e+01   6.600000000000000e+00   1.150000000000000e+01

>>

Cheers,
Andrew