Renamed 'reverse_codes()' to 'reversed()'.

pkg/DESCRIPTION

@@ -2,7 +2,7 @@ Package: memisc
 Type: Package
 Title: Management of Survey Data and Presentation of Analysis Results
 Version: 0.99.29
-Date: 2021-01-25
+Date: 2021-02-14
 Author: Martin Elff (with contributions from Christopher N. Lawrence, Dave Atkins, Jason W. Morgan, Achim Zeileis)
 Maintainer: Martin Elff <[email protected]>
 Description: An infrastructure for the management of survey data including

pkg/NAMESPACE

@@ -483,4 +483,4 @@ S3method(deduplicate_labels,item.list)
 
 export(trim_labels)
 exportMethods(trim_labels)
-export(reverse_codes)
+export(reversed)

pkg/R/reversed.R

@@ -0,0 +1,42 @@
+reversed.item <- function(x){
+    y <- x
+    if(length(labels(x))){
+        l <- labels(x)
+        vals <- vals.orig <- l@values
+        labs <- l@.Data
+        vf <- value.filter(x)
+        from <- vals[is.valid2(vals,vf)]
+        to <- rev(from)
+        for(i in seq_along(from)){
+            y[x==from[i]] <- to[i]
+            vals[vals.orig==from[i]] <- to[i]
+        }
+        to.l <- structure(vals,names=labs)
+        ii <- order(to.l)
+        to.l <- to.l[ii]
+        labels(y) <- to.l
+    } else {
+        v <- valid.values(x)
+        if(length(v)){
+            from <- v@filter
+            to <- rev(from)
+            for(i in seq_along(from)){
+                y[x==from[i]] <- to[i]
+            }
+        } else stop("No way to determine how reverse the codes.")
+    }
+    return(y)
+}
+
+
+
+
+reversed.factor <- function(x){
+    y <- factor(x,levels=rev(levels(x)))
+    return(y)
+}
+
+setGeneric("reversed",
+           function(x)standardGeneric("reversed"))
+setMethod("reversed","item.vector",reversed.item)
+setMethod("reversed","factor",reversed.factor)

pkg/inst/ChangeLog

@@ -1,3 +1,7 @@
+2021-02-14:
+   - Renamed 'reverse_codes()' to 'reversed()', which now leaves missing
+     values unchanged.
+
 2021-01-25:
    - Made function 'reorder_codes()' redundant and memoved it.
 

pkg/man/reversed.Rd

@@ -0,0 +1,42 @@
+\name{reversed}
+\alias{reversed}
+\alias{reversed,item.vector-method}
+\alias{reversed,factor-method}
+\title{Reverse the codes of a survey item or the levels of a factor}
+\description{
+The function \code{reversed()} returns a copy of its argument with codes
+or levels in reverse order.
+}
+\usage{
+reversed(x)
+\S4method{reversed}{item.vector}(x)
+\S4method{reversed}{factor}(x)
+}
+\arguments{
+  \item{x}{An object -- an "item" object or a "data.set" object}
+}
+\value{
+  If the argument of the function \code{reversed()} than either the
+  unique valid values or the labelled valid values recoded into the
+  reverse order.
+
+  If th argument is a factor than the function returns the factor with
+  levels in reverse order.
+}
+\examples{
+ds <- data.set(
+    x = as.item(sample(c(1:3,9),100,replace=TRUE),
+                labels=c("One"=1,
+                         "Two"=2,
+                         "Three"=3,
+                         "Missing"=9)))
+df <- as.data.frame(ds)
+ds <- within(ds,{
+    xr <- reversed(x)
+})
+codebook(ds)
+df <- within(df,{
+    xr <- reversed(x)
+})
+codebook(df)
+}