Re: [R] subsetting by groups, with conditions

Hi, I think you can also use plyr for this, dft - read.table(textConnection(P1idVeg1Veg2AreaPoly2 P2ID 1 p p 1 1 1 p p 1.5 2 2 p p 2 3 2 p h 3.5 4),

[R] subsetting by groups, with conditions

I have a data set similar to this: P1idVeg1Veg2AreaPoly2 P2ID 1 p p 1 1 1 p p 1.5 2 2 p p 2 3 2 p h 3.5 4 For each group of Poly1id records, I wish to

Re: [R] subsetting by groups, with conditions

try this: x - read.table(textConnection(P1idVeg1Veg2AreaPoly2 P2ID + 1 p p 1 1 + 1 p p 1.5 2 + 2 p p 2 3 + 2 p h 3.5 4), header=TRUE, as.is=TRUE) # split the

Re: [R] subsetting by groups, with conditions

Assuming your data frame is called DF we can use sqldf like this. The inner select calculates the maximum AreaPoly2 for each group such that Veg1 = Veg2 and the outer select returns the corresponding row. library(sqldf) sqldf(select * from DF a where AreaPoly2 = (select max(AreaPoly2)

Re: [R] subsetting by groups, with conditions

On Dec 28, 2009, at 7:03 PM, Seth W Bigelow wrote: I have a data set similar to this: P1idVeg1Veg2AreaPoly2 P2ID 1 p p 1 1 1 p p 1.5 2 2 p p 2 3 2 p h 3.5