What is the meaning of this simple 1 line matlab code?

X = [x, zeros(1,n)];

x is a 1xN matrix.

Answer 1

[Alok Nimrani]

Hi Minsoo Kim,

zeros(1,n) creates a 1xn vector of zeros i.e.

>> zeros(1,5)
ans =
     0     0     0     0     0

You can read more about ‘zeros’ at the following link: https://www.mathworks.com/help/matlab/ref/zeros.html

Now, ‘x’ is a 1xn vector and the operation being performed is:

>> X = [x zeros(1,n)];

Here, ‘[ ]’ is the matrix constructor operator and when the elements within the brackets are separated by space, the resulting matrix is a row-wise concatenation of the elements. So, the above operation is basically a row-wise concatenation of ‘x’ and ‘zeros(1,n)’. Check the following code as an example:

>> x = ones(1,5)
x =
     1     1     1     1     1

>> X = [x zeros(1,5)]
X =
     1     1     1     1     1     0     0     0     0     0

For more information about the matrix constructor operator '[ ]', you can check the following link: https://www.mathworks.com/help/matlab/math/creating-and-concatenating-matrices.html#f1-84906

Hope this clears your query.

Thanks.