[l m]=a(1,2,3;6,7,8) in matlab..........

is it possible to assign the elements of matrix a to [l m]?

[KALYANAPU SRINIVAS]

in the above question l=a[i][j] value i.e l=1 and m=a[i][j+1] value i.e m=6; and so on..... is the required answer. Please provide the code if exist

[Jan]

The question is not clear and the comment confuses me even more. What is "a[i][j]"? It is no valid Matlab syntax, but please do not let us guess if you mean C code or any other notation. Explain clearly what you want to get. "m=a[i][j+1] value i.e m=6"???

Answer 1

[KL]

1. You cannot assign two variables in one command unless it's a function return.
2. To define an array you should use "Square braces" --> [ ]
3. Then if you want to access the elements of a matrix, it goes like matrix_name(rowIndex, columnIndex))

For your case,

>> a = [1,2,3;6,7,8]

a =

       1     2     3
       6     7     8

>> l = a(1,1)

l =

       1

>> m = a(2,1)

m =

       6

In case you want all the values in the first row on l and second row on m, then

>> l = a(1,:)

l =

       1     2     3

>> m = a(2,:)

m =

       6     7     8

here : means all elements in the specified rowIndex.

[Stephen23]

1. Actually by creating a comma separated list it is possible (functions are not required):

>> C = {1,2};
>> [A,B] = C{:}
A =  1
B =  2

2. Square brackets are really a concatenation operator (not a list operator as some beginners think), which, because scalar values are of exactly the same class as matrices/arrays, simply create arrays by concatenating smaller arrays (which may be scalar) into larger arrays.

https://www.mathworks.com/help/matlab/matlab_prog/matlab-operators-and-special-characters.html

https://www.mathworks.com/help/matlab/math/creating-and-concatenating-matrices.html

3. See also: https://www.mathworks.com/help/matlab/math/matrix-indexing.html

[KL]

Thanks for the links Stephen. Yes, I'm familar with cell array returns while accessing its contents (as opposed to matrices). I'm just wondering, does it really make a difference calling it array concatenation? after all, we're creating a new array by using the square brackets, I think. Having said that, I appreciate you pushing people learn the better way.

[Stephen23]

"does it really make a difference calling it array concatenation?"

We regularly get questions here where people want to create lists (which MATLAB does not have), and they often mistake the [] operator for a list operator. It does cause some confusion for them. I believe that clarifying the concatenation role helps beginners to understand that all numeric values are arrays (even scalar arrays (aka "numbers")), as arrays are a first-class type in MATLAB.

So while the difference might be subtle and small, I think it is a point that is worth making, in order to understand MATLAB better.