How to unload a package without restarting R

Question

I'd like to unload a package without having to restart R (mostly because restarting R as I try out different, conflicting packages is getting frustrating, but conceivably this could be used in a program to use one function and then another--although namespace referencing is probably a better idea for that use). `?library` doesn't show any options that would unload a package. There is a suggestion that `detach` can unload package, but the following both fail: ``` detach(vegan) ``` Error in `detach(vegan)` : invalid `name` argument ``` detach("vegan") ``` Error in `detach("vegan")` : invalid `name` argument So how do I unload a package?

Accepted Answer

Try this (see `?detach` for more details):

```
detach("package:vegan", unload=TRUE)
```

It is possible to have multiple versions of a package loaded at once (for example, if you have a development version and a stable version in different libraries). To guarantee that all copies are detached, use this function.

```
detach_package <- function(pkg, character.only = FALSE)
{
  if(!character.only)
  {
    pkg <- deparse(substitute(pkg))
  }
  search_item <- paste("package", pkg, sep = ":")
  while(search_item %in% search())
  {
    detach(search_item, unload = TRUE, character.only = TRUE)
  }
}
```

Usage is, for example

```
detach_package(vegan)
```

or

```
detach_package("vegan", TRUE)
```

How to unload a package without restarting R

Solution

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