How to convert a single scalar value into a large matrix form

[Jay Bond]

Say I have a value of 2

How can I convert this into say a [50,1] matrix such that it is the same size to do some addition/subtraction with my other matrix

Currently I only know using mat X = (2\2\2\2), but I don't want to have to forward slash 50 times, is there a faster way?

[Mike Lacy]

My understanding is that you want a matrix in which each element has the value 2. For this purpose, see -help matrix functions-, where you will find documentation for the obscurely named but important function J(), to be used as follows;

mat X = J(50, 1, 2)

If you are doing a lot of matrix work, you might find Stata's Mata language useful for your ultimate purpose. Mata includes a syntax in which prefixing an arithmetic operator with a colon will apply that operation to each element of the matrix:

: mata
: X = 1\2\3\4\5
: X
       1
    +-----+
  1 |  1  |
  2 |  2  |
  3 |  3  |
  4 |  4  |
  5 |  5  |
    +-----+

: X = X :- 2

: X
        1
    +------+
  1 |  -1  |
  2 |   0  |
  3 |   1  |
  4 |   2  |
  5 |   3  |
    +------+

[Clyde Schechter]

Duplicate post. Asked and answered at https://www.statalist.org/forums/for...a-large-matrix.

Added: Crossed with #2.