Dear statalist,

I have a matrix in which two or more columns are exactly same. Is there some way of keeping one of them and dropping all others?

For example, I have the matrix

1 4 2 1 1
2 7 0 2 2
3 3 5 3 3

I want to drop the last two columns since they are same as the 1st column.

Thank you in advance.

Shoummo Sen Gupta