Confusion in Addition: adding 1:4 to a matrix of 1X4 gives resultant matrix of 1X5

If A = [1 0;0 1] then how would 1:4 + A(:)' = 1 2 3 4 5

Answer 1

[Guillaume]

Because of operator precedence, + has more priority than :. Therefore your expression is equivalent to :

1 : (4 + A(:)')

which is

1 : ([5; 4; 4; 5])

Because of the colon rule, only the first element of a vector is considered, the above is thus equivalent to:

1 : 5

I suspect you may have wanted

(1:4) + A(:)'

which will result in a 1x4 vector pre-R2016b (or it may error, I can't remember) and in a 4x4 matrix in R2016b or later.

[Ihsan Ullah]

Thanks Guillaume for your prompt positive support! Appreciated.