z_normalise: Normalise z values within a gtable object
Description
The z values within a gtable object can be any numeric values.
This function will change them to integers (starting from 1),
preserving the original order.
Usage
z_normalise(x, i = 1)
Arguments
x
A gtable object
i
The z value to start counting up from (default is 1)
Details
Ties are handled by the "first" method: the first occurrence
of a value wins.