Re: [R] with lapply() how can you retrieve the name of the object

From: Jorge Ivan Velez <jorgeivanvelez_at_gmail.com>
Date: Fri, 18 Jul 2008 18:31:54 -0400

Dear Andrew,

It's not the best solution but it does what you need:

a <- data.frame(var.1 = 1:5)
b <- data.frame(var.1 = 11:15)
test.list <- list(a=a, b=b)
res=do.call(rbind,test.list)
res$var.2=substr(rownames(res),1,1)
rownames(res)=NULL
res

HTH, Jorge

On Fri, Jul 18, 2008 at 6:21 PM, Andrew Yee <yee_at_post.harvard.edu> wrote:

> In the following code, I'd like to be able to create a new variable
> containing the value of the names of the list.
>
>
> a <- data.frame(var.1 = 1:5)
> b <- data.frame(var.1 = 11:15)
>
> test.list <- list(a=a, b=b)
>
> # in this case, names(test.list) is "a" and "b"
>
> # and I'd like to use lapply() so that
> # I get something that looks like
> # var.1 var.2
> # 1 a
> # 2 a
> # 3 a
> #etc.
>
> new.list <- lapply(test.list, function(x) {x$var.2 <- names(x)
> x} )
>
>
> # the above clearly doesn't do it. How do you pull out the names of the
> thing that is being lapplied?
>
> Thanks,
> Andrew
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
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>

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