How to convert array to tuple?

How can I convert an array

a = [1, 2, 3];

to a tuple

a = (1, 2, 3)

Or let's suppose that I have a matrix.

A = [1, 2; 3, 4]

and that I want to access the element of the second row first column element using an array [2, 1]. How can I do that? I.e. how can I get the element

A(2,1)

doing something like A([2,1]). I'm just looking for something similar to python which would be

A(tuple([1,2]))

[Stephen23]

"How to convert array to tuple?"

MATLAB does not have tuples. It has arrays of various classes. There are numeric arrays (e.g. double, single, int8, etc), or character arrays, or logical arrays, and some are container arrays (which can contain other arrays, e.g. cell, struct, table, etc).

It is not clear what you are trying to achieve with this:

A(tuple([1,2]))

What do you expect the output to be?

Answer 1

[Walter Roberson]

MATLAB does not have tuples.

You can use sub2ind to convert multiple subscripts to linear indices.

MATLAB does have comma separated lists. It would be valid to do

T = num2cell(a) ;
A(T{:})

Unfortunately there does not appear to be any way in MATLAB to combine those two steps without using an intermediate true function, at least not in the general multidimensional case. You can always define something like

tuple2 = @(A,v) sub2ind(size(A), v(1), v(2))

After which you could use

A(tuple2(A, a))

But it hardly seems worth it.