detach                 package:base                 R Documentation

_D_e_t_a_c_h _O_b_j_e_c_t_s _f_r_o_m _t_h_e _S_e_a_r_c_h _P_a_t_h

_D_e_s_c_r_i_p_t_i_o_n:

     Detach a database, i.e., remove it from the 'search()' path of
     available R objects.  Usually, this is either a 'data.frame' which
     has been 'attach'ed or a package which was required previously.

_U_s_a_g_e:

     detach(name, pos = 2, version)

_A_r_g_u_m_e_n_t_s:

    name: The object to detach.  Defaults to 'search()[pos]'. This can
          be an unquoted name or a character string but _not_ a
          character vector.  If a number is supplied this is taken as
          'pos'. 

     pos: Index position in 'search()' of database to detach.  When
          'name' is a number, 'pos = name' is used. 

 version: A character string denoting a version number of the package
          to be removed.  This should be used only with a versioned
          installation of the package: see 'library'.

_D_e_t_a_i_l_s:

     This most commonly used with a single number argument referring to
     a position on the search list, and can also be used with a
     unquoted or quoted name of an item on the search list such as
     'package:tools'.

     When a package have been loaded with an explicit version number it
     can be detached using the name shown by 'search' or by supplying
     'name' and 'version': see the examples.

_V_a_l_u_e:

     The attached database is returned invisibly, either as
     'data.frame' or as 'list'.

_N_o_t_e:

     You cannot detach either the workspace (position 1) or the 'base'
     package (the last item in the search list).

_R_e_f_e_r_e_n_c_e_s:

     Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) _The New S
     Language_. Wadsworth & Brooks/Cole.

_S_e_e _A_l_s_o:

     'attach', 'library', 'search', 'objects'.

_E_x_a_m_p_l_e_s:

     require(splines)#package
     detach(package:splines)
     ## could equally well use detach("package:splines")
     ## but NOT  pkg <- "package:splines"; detach(pkg)
     ## Instead, use
     library(splines)
     pkg <- "package:splines"
     detach(pos = match(pkg, search()))

     ## careful: do not do this unless 'splines' is not already loaded.
     library(splines)
     detach(2)# 'pos' used for 'name'

     ## an example of the name argument to attach
     ## and of detaching a database named by a character vector
     attach_and_detach <- function(db, pos=2)
     {
        name <- deparse(substitute(db))
        attach(db, pos=pos, name=name)
        print(search()[pos])
        eval(substitute(detach(n), list(n=name)))
     }
     attach_and_detach(women, pos=3)

     ## Not run: 
     ## Using a versioned install
     library(ash, version="1.0-9")  # or perhaps just library(ash)
     # then one of
     detach("package:ash", version="1.0-9")
     # or
     detach("package:ash_1.0-9")
     ## End(Not run)

