Stack and sort a vector up to calculated z value

Why didn't you attach your worksheet?

Try

This approach will fail if no value in z.soil is larger than z.cal.

If this is a problem, you may use tray and catch to cope with it

Remarks

Now this approach would give a wrong result if ALL values in z.soil are larger than z.cal.

If z.cal is equal to a value in z.soil, this value will be seen twice at the end of the resulting vector - not sure if this is desired behaviour.

If the values in z.soil are not sorted, you should use sort(trim(....)).

Here is a version which also considers these points. I formulated it as function of z.cal because this makes testing all possible cases easier