[R] partially sum variable of a dataframe

[Julian Burgos]

I'm assuming that you want to add b if 3<a<5.25.  If so, there are many 
ways.  One of them is

sum (b[a>3 & a<5.25])

This is very simple R coding.  I recommend you spend some time learning 
the basics.  There are very good tutorials at the R website.

Julian

mdgi at gmx.ch wrote:
> Hello,
> 
> A stupid question:
> 
> I have an array with two columns, the first "a" acting as my index in 0.25 steps, the second one "b" the column of interest. How can i sum up "b" only for a specified window in "a" (as the window command for time series)
> 
> a=seq(0,10,0.25)
> b=runif(41)
> c=data.frame(a,b)
> 
> Sum up c if 3<a<5.25
> 
> How to do that? thanks
> 
> marc