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

From: jim holtman <jholtman_at_gmail.com>
Date: Fri, 18 Jul 2008 19:00:19 -0400

forgot one step:

> z <- lapply(names(test.list), function(x){
+ cbind(test.list[[x]], var.2=x)
+ })
> names(z) <- names(test.list)
> z

$a
  var.1 var.2

1     1     a
2     2     a
3     3     a
4     4     a
5     5     a

$b
  var.1 var.2

1    11     b
2    12     b
3    13     b
4    14     b
5    15     b

>

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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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

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Received on Fri 18 Jul 2008 - 23:03:37 GMT

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