How to specify the package when looking up a help reference page for a function?

Question

How does one look up the help manual page for a function and specify the package in R? For example, count appears in both seqinr and plyr. If I want to look up count in plyr, what's the command? I've tried a few obvious (but wrong) guesses such as "?plyr::count"

EDIT: When I do ?count, I get the following message:

Help on topic 'count' was found in the following packages:

  Package               Library
  plyr                  /Library/Frameworks/R.framework/Versions/2.15/Resources/library
  seqinr                /Library/Frameworks/R.framework/Versions/2.15/Resources/library

When I do ?plyr::count, I get:

No documentation for 'plyr::count' in specified packages and libraries:
you could try '??plyr::count'

When I do ?plyr:::count, I get:

No documentation for 'plyr:::count' in specified packages and libraries:
you could try '??plyr:::count'

Adding two question marks also gets me a no documentation found error as well. Looking up help for non-ambiguous funcitons is working fine (e.g. ?plot)

This is with R 2.15.0 on OSX running in emacs + ESS.

Answer 1

Use the package= argument to help:

help("count", package="plyr")

Answer 2

The correct way to do this is:

?plyr::count
?plyr:::count

See ?"?" for details - both examples are shown.

Both work for me with both packages loaded and even without the package loaded. That begs the question if you have the packages installed?

Answer 3

You were close, you need three : :::

?seqinr:::count # for seqinr
?plyr:::count # for plyr