The R Project SVN R-packages

### $Id: spss.R,v 1.5 2002/04/29 19:48:37 saikat Exp $
###
###             Read SPSS system data files
###
### Copyright 2000-2002 Saikat DebRoy <saikat$stat.wisc.edu>
###                     Douglas M. Bates <bates$stat.wisc.edu>,
###                     Thomas Lumley
### This file is part of the `foreign' library for R and related languages.
### It is made available under the terms of the GNU General Public
### License, version 2, or at your option, any later version,
### incorporated herein by reference.
### 
### This program is distributed in the hope that it will be
### useful, but WITHOUT ANY WARRANTY; without even the implied
### warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
### PURPOSE.  See the GNU General Public License for more
### details.
### 
### You should have received a copy of the GNU General Public
### License along with this program; if not, write to the Free
### Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
### MA 02111-1307, USA

read.spss <- function(file,use.value.labels=TRUE,to.data.frame=FALSE,
                      max.value.labels=Inf, trim.factor.names=FALSE) {

  
    trim<-function(strings){
      if (trim.factor.names)
        gsub(" +$","",strings)
      else
        strings
    }
  
  
    rval<-.Call("do_read_SPSS", file, PACKAGE = "foreign")
    
    
    vl<-attr(rval,"label.table")
    has.vl<-which(!sapply(vl,is.null))
    for(v in has.vl){
      nm<-names(vl)[[v]]
      nvalues<-length(na.omit(unique(rval[[nm]])))
      nlabels<-length(vl[[v]])
      if (use.value.labels &&
          (!is.finite(max.value.labels) || nvalues<=max.value.labels) &&
          nlabels>=nvalues)
        rval[[nm]]<-factor(rval[[nm]], levels=vl[[v]], labels=trim(names(vl[[v]])))
      else
        attr(rval[[nm]],"value.labels")<-vl[[v]]
    }
    
    
    if (to.data.frame) {
      varlab <- attr(rval, "variable.labels")
      rval <- as.data.frame(rval)
      attr(rval, "variable.labels") <- varlab
    }
    rval
}