[R] r: functions

[TEMPL Matthias]

Hello,

I have no errors with simple1:

d <- matrix(c(1,2,3,1,6,10,10,6,7),ncol=3)
colnames(d) <- c("one", "two", "three")
x<- d[,c(1,2)]
y<-d[,3]

> y
[1] 10  6  7

> simple1(x,y)
[[1]]

Call:
lm(formula = ydata ~ xdata)

Coefficients:
(Intercept)     xdataone     xdatatwo  
         -6           21           -5  


With:
y <-d[,3, drop=FALSE]

> y
     [,1]
[1,]   10
[2,]    6
[3,]    7

> simple1(x,y)
[[1]]

Call:
lm(formula = ydata ~ xdata)

Coefficients:
(Intercept)     xdataone     xdatatwo  
         -6           21           -5   

You have an error with function simple, which you have not shown! (you have only shown function simple1, simple2 and simple3)

Look at simple3 now:
simple3<-function(xdata,ydata)
{
	datas<-data.frame(xdata=xdata,ydata=ydata)
	ofit<-lm(ydata~xdata, data=datas)
	list(ofit)
}

> simple3(x,y)
[[1]]

Call:
lm(formula = ydata ~ xdata, data = datas)

Coefficients:
(Intercept)     xdataone     xdatatwo  
         -6           21           -5  

Best,
Matthias


> -----Ursprüngliche Nachricht-----
> Von: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] Im Auftrag von Clark Allan
> Gesendet: Donnerstag, 24. Februar 2005 10:17
> An: r-help at stat.math.ethz.ch
> Betreff: [R] r: functions
> 
> 
> hi all
> 
> 
> i have a function that uses two inputs, say xdata and ydata. 
> An example is the following,
> 
> simple1<-function(xdata,ydata)
> {
> 	ofit<-lm(ydata~xdata)
> 	list(ofit)
> }
> 
> say i use arbitray number for xdata and ydata such that
> 
> D = 
> x1	x2	y
> 1	1	10
> 2	6	6
> 3	10	7
> 
> 
> x<-D[,1:2]
> 
> and 
> 
> y<-D[,3]
> 
> if one uses these inputs and rund the program we get the following:
> 
> >simple(xdata=x,ydata=y)
> Error in model.frame(formula, rownames, variables, varnames, 
> extras, extranames,  : 
>         invalid variable type
> 
> why does this happen!
> 
> i can get results if i change the program as follows:
> 
> simple2<-function(xdata,ydata)
> {
> 	ofit<-lm(as.matrix(ydata)~as.matrix(xdata))
> 	list(ofit)
> }
> 
> but then the variable names, if they exist, are not 
> preserved. how can i preserve these names.
> 
> the results are now:
> 
> > simple2(xdata=x,ydata=y)
> [[1]]
> 
> Call:
> lm(formula = as.matrix(ydata) ~ as.matrix(xdata))
> 
> Coefficients:
>        (Intercept)  as.matrix(xdata)x1  as.matrix(xdata)x2  
>                 -6                  21                  -5  
> 
> i've tried converting xdata and ydata to data frames but i 
> still get errors.
> 
> simple3<-function(xdata,ydata)
> {
> 	xdata<-as.data.frame(xdata)
> 	ydata<-as.data.frame(ydata)
> 	ofit<-lm(ydata~xdata)
> 	list(ofit)
> }
> 
> i.e.
> 
> > simple3(xdata=x,ydata=y)
> Error in model.frame(formula, rownames, variables, varnames, 
> extras, extranames,  : 
>         invalid variable type
> 
> please help!
> 
> thanking you in advance
> 
> ***
> allan
>