What is the difference between the statements: A=2; A=(2); A=[2]?

I am a beginner, got a question about it When making an assignment, it usually uses A=2, and it is also understandable that A=[2] as matrix form. But what's the point of A=(2) here that returns the same value? it works when I am trying to change a value to a matrix.

[Andreas Goser]

Do you ask, because you reuse code that is created like that?

[edvyan]

For a created matrix, i.e. A=[1 2 3;4 5 6], if I want to change the element 2 to 8, we normally use A(2)=8 or uncommonly A(2)=[8]. But why A(2)=(8) returns the same answer [1 2 3;8 5 4] rather than an error notice?

[Paulo Silva]

It depends where the parenthesis are located on the expression, if you put the ( after the variable it means you are going to insert index or indices values, if you put ( after the equal it will be ignored.

Answer 1

[Paulo Silva]

In MATLAB values like [2] and (2) are the same as 2, for the ( type they mean other things when used after a variable or function.

now for more values

A=[1 2 3] %same as A=1:3

A is now a vector and if you do A(2) you get the second value of the vector A which is 2

Please read this Matrices and Magic Squares

[Oleg Komarov]

The square brackets should cause a small overhead for calling the concatenation.

[Teja Muppirala]

When used in loop indices, square brackets will make things very slow:

%% Very fast

tic

x = 0;

for n = 1:1e6

x = x+1;

end

x

toc

%% Very slow

tic

x = 0;

for n = [1:1e6]

x = x+1;

end

x

toc

Answer 2

[Fangjun Jiang]

To merely answer your question.

A=2 is the same as A=[2], is because 2 is a special case of a matrix with size as 1x1.

A=2 is the same as A=(2), is because 2 can be regarded as a special case of an calculation, for example, it could be A=(4-3)*2

You may want to learn other use of (),{} and [] in MATLAB. Type 'help {' to see a list of symbols and their use.