frametools

git-svn-id: https://svn.r-project.org/R/branches/R-0-61-patches@896 00db46b3-68df-0310-9c12-caf00c1e9a41

src/library/base/R/frametools

@@ -0,0 +1,54 @@
+subset.data.frame <-
+function (dfr, subset, select) 
+{
+	if(missing(subset))
+		r<-NULL
+	else {
+		e <- substitute(subset)
+		r <- eval(e,dfr)
+		r <- r & !is.na(r)
+	}
+	if(missing(select))
+		vars<-NULL
+	else {
+		nl<-as.list(1:ncol(dfr))
+		names(nl)<-names(dfr)
+		vars<-eval(substitute(select),nl)
+	}
+	dfr[r,vars,drop=F]
+}
+
+subset<-
+function(x,...)
+	UseMethod("subset")
+
+subset.default <- 
+function(x,subset) 
+	x[subset & !is.na(subset)]
+
+transform.data.frame <-
+function (dfr, ...) 
+{
+        e <- eval(substitute(list(...)), dfr)
+        tags <- names(e)
+        inx <- match(tags, names(dfr))
+        matched <- !is.na(inx)
+        if (any(matched)) {
+                dfr[inx[matched]] <- e[matched]
+		dfr<-data.frame(dfr)
+	}
+        if (!all(matched)) 
+                data.frame(dfr, e[!matched])
+        else dfr
+}
+
+transform <-
+function(x,...)
+	UseMethod("transform")
+
+# Actually, I have no idea what to transform(), except dataframes.
+# The default converts its argument to a dataframe and transforms
+# that. This is probably marginally useful at best. --pd
+transform.default <- 
+function(x,...)
+	transform.data.frame(data.frame(x),...)