Yes!It works well and really what I want!
Many thanks for your help!
Merry Christmas.
At 2012-12-24 22:15:36,arun <smartpink...@yahoo.com> wrote:
>Hi,
>How about this?
>
>set.seed(5)
>dat<-data.frame(x=sample(1:20,6,replace=TRUE),a=sample(20:40,6,replace=TRUE))
> dat1<-within(dat,{f=a/median(a);x_new=x*f})
> dat1
># x a x_new f
>#1 5 31 5.081967 1.0163934
>#2 14 36 16.524590 1.1803279
>#3 19 40 24.918033 1.3114754
>#4 6 22 4.327869 0.7213115
>#5 3 25 2.459016 0.8196721
>#6 15 30 14.754098 0.9836066
>
>#or
> res<-do.call(data.frame,lapply(lapply(1,function(y) dat),function(y)
> {y$f<-y$a/median(y$a);y$x_new<-y$f*y$x;y}))
>A.K.
>
>
>
>
>
>
>________________________________
>From: meng <laomen...@163.com>
>To: arun <smartpink...@yahoo.com>
>Cc: R help <r-help@r-project.org>
>Sent: Monday, December 24, 2012 5:29 AM
>Subject: Re:Re: [R] How to do it through 1 step?
>
>
>Yes,this is my final solution,but if I wanna add many new variables,and maybe
>the following "new variables" are computed based on the previous " new
>variables", this solution maybe difficult.
>
>
>
>
>
>
>
>
>At 2012-12-24 17:01:03,arun <smartpink...@yahoo.com> wrote:
>>HI,
>>
>>Not sure if this works for you.
>>set.seed(5)
>>dat<-data.frame(x=sample(1:20,6,replace=TRUE),a=sample(20:40,6,replace=TRUE))
>> dat1<-transform(dat,f=a/median(a),x_new=x*(a/median(a)))
>> head(dat1,2)
>># x a f x_new
>>#1 5 31 1.016393 5.081967
>>#2 14 36 1.180328 16.524590
>>A.K.
>>
>>
>>
>>
>>----- Original Message -----
>>From: meng <laomen...@163.com>
>>To: r-help@r-project.org
>>Cc:
>>Sent: Monday, December 24, 2012 12:55 AM
>>Subject: [R] How to do it through 1 step?
>>
>>A data set(dat),has 2 variables: x and a, and 100 rows.
>>
>>I wanna add 2 variables,and call the new data set dat1:
>>var1:f = a/median(a)
>>var2:x_new = x*f
>>
>>My solution:
>>dat1<-transform(dat,f = a/median(a),x_new = x*f)
>>But gets error reply which says that "f" is not exits since dat has no
>>variables called "f".
>>
>>So I have to do through 2 steps:
>>dat0<-transform(dat,f=a/median(a))
>>dat1<-transform(dat0,x_new=x*f)
>>
>>How to do it through 1 step?
>>
>>Many thanks!
>>
>>
>> [[alternative HTML version deleted]]
>>
>>______________________________________________
>>R-help@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.
>>
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