num_to_admin: Convert Numeric Code to Administrative Level String
Description
This function converts a numerical administrative level into its corresponding
string format.
Usage
num_to_admin(num)
Value
A character string representing the administrative level:
- 0 is converted to "National".
- Positive integers are converted to "Admin-X".
- Returns NULL if the input is invalid.
Arguments
num
A single integer representing the administrative level.
The value 0 corresponds to "National", while positive integers correspond to "Admin-X".