问题
When I loaded package debug to debug a script with zoo objects, I got trouble: function index from zoo got masked by debug package. How can I unmask index? In general, how to deal with these name colliding problems? We just do not use debug package with `zoo'?
回答1:
Exported symbols are always identifiable with the :: operator:
zoo::index
Hidden functions not declared in the namespace can still be accessed using ::: (triple-colon), and example would be
zoo:::.onLoad
which you can see even though it is not exported.
回答2:
You can unload the package which has masked functions and then reload it. It will regain precedence in the searchpath:
unloadNamespace("zoo")
library("zoo")
In the future, if you want to load a package while preventing it from masking other functions, you can specify its position in the search path with an arbitrary large number:
library("debug", pos = .Machine$integer.max)
回答3:
Its only masked to you but its not masked to zoo so when a zoo function tries to use index it will still find its own index first.
zoo also has a time.zoo method so if z is a zoo object you can use time(z) in place of index(z).
Finally you can always refer to zoo::index to make sure you get the one in zoo.
来源：https://stackoverflow.com/questions/3241539/how-to-unmask-a-function-in-r-due-to-name-collisions-on-searchpath