"Accuracy" function in "forecast" package of R 3.0.2

Question

I installed R version 3.0.2 on Mac OS X 10.8.4, then tried to install "forecast" package using install.package("forecast")

However, although the packageVersion("forecast") shows me the 4.8 version (which means it is installed) and the accuracy function is well described in forecast package version 4.8 document (http://cran.r-project.org/web/packages/forecast/forecast.pdf), I cannot use accuracy function and when I use help function, this is the response:

> help("accuracy")

no documentation for ‘accuracy’ in specified packages and libraries:
you could try ‘??accuracy’

Could anyone help me with the problem in installation?

Answer 1

You need to load the package before you can use it or before you can view the help file without specifying the package

library(forecast) # or require(forecast)
help("accuracy")
# or
?accuracy

If you don't want to load the library you can just specify the package

help("accuracy", package = "forecast")

but in general just installing the package doesn't load it automatically.