Creating matrix with same value elements

I have calculated a value. I need to turn the value into a 1 x n matrix. All of the elements in the matrix are the same value.

Ex
Value = 1400
n = 4

want to get; Tsel = [1400, 1400, 1400, 1400]

I'm drawing a horizontal line across a graph to be able to pick off the horizontal value.

Two side questions;
1. I using ginput to select some values off of a graph, is there any to see the coordinate values as I move the cursor around.

2. Is there any way to concatenate a calculated value in the text function for a graph.