R help - Sep 2010 - how to make list() return a list of *named* elements

If I combine elements into a list

b <- c(22.4, 12.2, 10.9, 8.5, 9.2)
my.c <- sample.int(round(2*mean(b)), 5)
my.list <- list(b, my.c)

the names of the elements seems to get lost in the process:
> str(my.list)
List of 2
 $ : num [1:5] 22.4 12.2 10.9 8.5 9.2
 $ : int [1:5] 11 8 6 9 20

If I explicitly name the elements at list-creation, I get what I want:

my.list <- list(b=b, my.c=my.c)
> str(my.list)
List of 2
 $ b   : num [1:5] 22.4 12.2 10.9 8.5 9.2
 $ my.c: int [1:5] 11 8 6 9 20


Now, is there a way to get list() (or some other function) to
automatically name the elements?

I often use list() in return(), and I am getting tired of having to
repeat myself.

-- 
Hans Ekbrand (http://sociologi.cjb.net) <hans at sociologi.cjb.net>
A. Because it breaks the logical sequence of discussion
Q. Why is top posting bad?
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You should try:

eapply(.GlobalEnv, I)[c('b', 'my.c')]


On Thu, Sep 30, 2010 at 8:49 AM, Hans Ekbrand
<hans.ekbrand@sociology.gu.se>wrote:
> If I combine elements into a list
>
> b <- c(22.4, 12.2, 10.9, 8.5, 9.2)
> my.c <- sample.int(round(2*mean(b)), 5)
> my.list <- list(b, my.c)
>
> the names of the elements seems to get lost in the process:
>
> > str(my.list)
> List of 2
>  $ : num [1:5] 22.4 12.2 10.9 8.5 9.2
>  $ : int [1:5] 11 8 6 9 20
>
> If I explicitly name the elements at list-creation, I get what I want:
>
> my.list <- list(b=b, my.c=my.c)
>
> > str(my.list)
> List of 2
>  $ b   : num [1:5] 22.4 12.2 10.9 8.5 9.2
>  $ my.c: int [1:5] 11 8 6 9 20
>
>
> Now, is there a way to get list() (or some other function) to
> automatically name the elements?
>
> I often use list() in return(), and I am getting tired of having to
> repeat myself.
>
> --
> Hans Ekbrand (http://sociologi.cjb.net) <hans@sociologi.cjb.net>
> A. Because it breaks the logical sequence of discussion
> Q. Why is top posting bad?
>
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> and provide commented, minimal, self-contained, reproducible code.
>
>

-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

On Thu, Sep 30, 2010 at 7:49 AM, Hans Ekbrand
<hans.ekbrand at sociology.gu.se> wrote:
> If I combine elements into a list
>
> b <- c(22.4, 12.2, 10.9, 8.5, 9.2)
> my.c <- sample.int(round(2*mean(b)), 5)
> my.list <- list(b, my.c)
>
> the names of the elements seems to get lost in the process:
>
>> str(my.list)
> List of 2
> ?$ : num [1:5] 22.4 12.2 10.9 8.5 9.2
> ?$ : int [1:5] 11 8 6 9 20
>
> If I explicitly name the elements at list-creation, I get what I want:
>
> my.list <- list(b=b, my.c=my.c)
>
>> str(my.list)
> List of 2
> ?$ b ? : num [1:5] 22.4 12.2 10.9 8.5 9.2
> ?$ my.c: int [1:5] 11 8 6 9 20
>
>
> Now, is there a way to get list() (or some other function) to
> automatically name the elements?
>
> I often use list() in return(), and I am getting tired of having to
> repeat myself.
A data frame is a list in which every component (i.e. every column)
must have the same length (i.e. the same number of rows).
data.frame() does preserve names:
> data.frame(b, my.c)
     b my.c
1 22.4    8
2 12.2    9
3 10.9   15
4  8.5    1
5  9.2   14


-- 
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

On Thu, Sep 30, 2010 at 09:10:16AM -0400, Gabor Grothendieck
wrote:
> A data frame is a list in which every component (i.e. every column)
> must have the same length (i.e. the same number of rows).
> data.frame() does preserve names:
> 
> > data.frame(b, my.c)
>      b my.c
> 1 22.4    8
> 2 12.2    9
> 3 10.9   15
> 4  8.5    1
> 5  9.2   14
Thanks for your suggestion. However, the reason I used list() was that
the different vectors to return usually have different lengths.

Admittedly, I should have used another example that explicated this.

-- 
Hans Ekbrand (http://sociologi.cjb.net) <hans at sociologi.cjb.net>
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On Mon, Oct 04, 2010 at 07:51:10PM +0800, Berwin A Turlach
wrote:
> R> my.return <- function (vector.of.variable.names) {  
>      sapply(vector.of.variable.names, function(x) get(x))
>    }
Even better :-)

-- 
Hans Ekbrand (http://sociologi.cjb.net) <hans at sociologi.cjb.net>
GPG Fingerprint: 1408 C8D5 1E7D 4C9C C27E 014F 7C2C 872A 7050 614E
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On Mon, Oct 4, 2010 at 7:51 AM, Berwin A Turlach
<berwin at maths.uwa.edu.au> wrote:
> On Mon, 4 Oct 2010 19:45:23 +0800
> Berwin A Turlach <berwin at maths.uwa.edu.au> wrote:
>
> Mmh,
>
>> R> my.return <- function (vector.of.variable.names) {
>> ? sapply(vector.of.variable.names, function(x) list(get(x)))
>> }
>
> make that:
>
> R> my.return <- function (vector.of.variable.names) {
> ? ? sapply(vector.of.variable.names, function(x) get(x))
> ? }
>
Some small tweaks.   If you use simplify=FALSE then it will guarantee
that a list is returned:

   sapply(my.names, get, simplify = FALSE)

for example, compare the outputs of:

   sapply(c("letters", "LETTERS"), get)
   sapply(c("letters", "LETTERS"), get, simplify = FALSE)

-- 
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

See llist from Hmisc package:

library(Hmisc)
a=rnorm(10)
b=rnorm(5)
llist(a,b)



On Thu, Sep 30, 2010 at 1:49 PM, Hans Ekbrand
<hans.ekbrand at sociology.gu.se> wrote:
> If I combine elements into a list
>
> b <- c(22.4, 12.2, 10.9, 8.5, 9.2)
> my.c <- sample.int(round(2*mean(b)), 5)
> my.list <- list(b, my.c)
>
> the names of the elements seems to get lost in the process:
>
>> str(my.list)
> List of 2
> ?$ : num [1:5] 22.4 12.2 10.9 8.5 9.2
> ?$ : int [1:5] 11 8 6 9 20
>
> If I explicitly name the elements at list-creation, I get what I want:
>
> my.list <- list(b=b, my.c=my.c)
>
>> str(my.list)
> List of 2
> ?$ b ? : num [1:5] 22.4 12.2 10.9 8.5 9.2
> ?$ my.c: int [1:5] 11 8 6 9 20
>
>
> Now, is there a way to get list() (or some other function) to
> automatically name the elements?
>
> I often use list() in return(), and I am getting tired of having to
> repeat myself.
>
> --
> Hans Ekbrand (http://sociologi.cjb.net) <hans at sociologi.cjb.net>
> A. Because it breaks the logical sequence of discussion
> Q. Why is top posting bad?
>
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> d8UAnRskbOM7mDhDexiS7T9LkhRs287P
> =MsDG
> -----END PGP SIGNATURE-----
>
> ______________________________________________
> R-help at 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.
>
>


-- 
Christophe Pallier? <christophe at pallier.org>
tel: +33 (0)1 69 08 79 34
Unit? de Neuroimagerie Cognitive INSERM-CEA,
Neurospin center, F91191 Gif-sur-Yvette, France
web site: http://www.unicog.org
personal web site: www.pallier.org

On Mon, Oct 04, 2010 at 04:10:46PM +0200, Christophe Pallier
wrote:
> See llist from Hmisc package:
> 
> library(Hmisc)
> a=rnorm(10)
> b=rnorm(5)
> llist(a,b)
Ah, that seems like what I want!

My old, ugly and redunant code looked like this

  list(utdrag=utdrag,
      
n.fires.at.sites.with.one.or.more.fires=n.fires.at.sites.with.one.or.more.fires,
      
more.than.one.fire.in.these.clusters=more.than.one.fire.in.these.clusters,
      
n.fires.in.clusters.with.more.than.one.fire=n.fires.in.clusters.with.more.than.one.fire,
       n.fires.in.top.ten.clusters=n.fires.in.top.ten.clusters,
       m=m,
       ?versta.fem.procenten=?versta.fem.procenten,
       these.cluster.have.alot.of.members=these.cluster.have.alot.of.members,
       n.fires.in.hotspots=n.fires.in.hotspots,
       prop.concentrated.fires=prop.concentrated.fires,
       d=d,
       real.vector=real.vector,
       the.real=the.real,
       censored.real=censored.real,
       half.of.effect.at=half.of.effect.at)

The new, nice-looking code looks like this:

  llist(utdrag,
        n.fires.at.sites.with.one.or.more.fires,
        more.than.one.fire.in.these.clusters,
        n.fires.in.clusters.with.more.than.one.fire,
        n.fires.in.top.ten.clusters,
        m,
        ?versta.fem.procenten,
        these.cluster.have.alot.of.members,
        n.fires.in.hotspots,
        prop.concentrated.fires,
        d,
        real.vector,
        the.real,
        censored.real,
        half.of.effect.at)

Thank you all r-helpers!
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