R help - Jul 2011 - for/if loop in R

hi,

Can someone please help me figure out where I am making a mistake in my for/if
loop:

I have a data frame (112 rows) called pricedata with 3 columns: date, prices,
return.

Now, I want to add a 4th column, trend, which can have 2 values 0 or 1. if
return>1%, trend=1 else trend=0.

so, this is what I did:
>trend<-numeric(nrow(pricedata))
>cbind(pricedata,trend)
>for(i in 2:nrow(pricedata)){
+if (return[i]>0.01) trend[i]=1 else trend[i]=0
+}

and it doesn't change the values in trend, despite the fact that the return
column has several rows with values >0.01 -why?

thx!




 		 	   		  
	[[alternative HTML version deleted]]

For me, this works:
> Now, I want to add a 4th column, trend
pricedata$trend <- 0
> which can have 2 values 0 or 1. if return>1%, trend=1 else trend=0.
pricedata$trend <- ifelse( pricedata$return > .01, 1, 0 )

Rgds,
Rainer


On Thursday 21 July 2011 19:39:15 financial engineer
wrote:
> 
> hi,
> 
> Can someone please help me figure out where I am making a mistake in my
for/if loop:
> 
> I have a data frame (112 rows) called pricedata with 3 columns: date,
prices, return.
> 
> Now, I want to add a 4th column, trend, which can have 2 values 0 or 1. if
return>1%, trend=1 else trend=0.
> 
> so, this is what I did:
> >trend<-numeric(nrow(pricedata))
> >cbind(pricedata,trend)
> >for(i in 2:nrow(pricedata)){
> +if (return[i]>0.01) trend[i]=1 else trend[i]=0
> +}
> 
> and it doesn't change the values in trend, despite the fact that the
return column has several rows with values >0.01 -why?
> 
> thx!
> 
> 
> 
> 
>  		 	   		  
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.