MATLAB: What is the result

Question

X a matrix 2 × n containing the coordinates of n points of the plan. How to obtain a matrix where the points are ordered by ascending order of the x-axis?

Answer 1

n = 100 ;
X = rand(2,n) ;  % some random data 
[val,idx] = sort(X(1,:),'ascend') ;   % sort x values (first row) in ascending order 
X = X(:,idx) ;