t; > From: r-help-boun...@r-project.org
> > [mailto:r-help-boun...@r-project.org] On Behalf Of hadley wickham
> > Sent: Friday, October 02, 2009 6:07 AM
> > To: jim holtman
> > Cc: r-help@r-project.org; Kavitha Venkatesan
> > Subject: Re: [R] split-apply quest
> -Original Message-
> From: r-help-boun...@r-project.org
> [mailto:r-help-boun...@r-project.org] On Behalf Of hadley wickham
> Sent: Friday, October 02, 2009 6:07 AM
> To: jim holtman
> Cc: r-help@r-project.org; Kavitha Venkatesan
> Subject: Re: [R] split-apply ques
On Fri, Oct 2, 2009 at 4:24 AM, jim holtman wrote:
> try this:
>
>> x <- read.table(textConnection("x1 x2 x3
> + A 1 1.5
> + B 2 0.9
> + B 3 2.7
> + C 7 1.8
> + D 7 1.3"), header=TRUE)
>> closeAllConnections()
>> do.call(rbind, lapply(split(seq(nrow(x)), x$x1), function(
You can use aggregate:
aggregate(x[,c('x2','x3')], x['x1'], min)
On Fri, Oct 2, 2009 at 12:43 AM, Kavitha Venkatesan
wrote:
> Hi,
>
> I have a data frame that looks like this:
>
>>x
>
> x1 x2 x3
> A 1 1.5
> B 2 0.9
> B 3 2.7
> C 7 1.8
> D 7 1.3
>
> I want to "group" by
As is typical with R there are often other ways. Here is another
approach that determines the rows of interest with tapply and min,
converts those minimums into logical "targets" with %in%, and extracts
them from "x" using indexing:
x[x$x2 %in% tapply(x$x2, x$x1, min), ]
x1 x2
try this:
> x <- read.table(textConnection("x1 x2 x3
+ A 11.5
+ B 20.9
+ B 32.7
+ C 71.8
+ D 71.3"), header=TRUE)
> closeAllConnections()
> do.call(rbind, lapply(split(seq(nrow(x)), x$x1), function(.row){
+ x[.row[which.min(x$x2[.row])],]
+ }))
x1 x2 x3
A A
?subset is probably what you want:
subset(x, x1 == 'A')
On Oct 2, 1:43 pm, Kavitha Venkatesan
wrote:
> Hi,
>
> I have a data frame that looks like this:
>
> >x
>
> x1 x2 x3
> A 1 1.5
> B 2 0.9
> B 3 2.7
> C 7 1.8
> D 7 1.3
>
> I want to "group" by the x1 column and in
Hi,
I have a data frame that looks like this:
>x
x1 x2 x3
A 11.5
B 20.9
B 32.7
C 71.8
D 71.3
I want to "group" by the x1 column and in the case of multiple x$x1 values
(e.g., "B")d, return rows that have the smallest values of x2. In the case
of rows with only on
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