R help - Jun 2003 - Paste and namespace

Hi, my doubt is very simple. I'm sure I've seen someone using something
like this before, but unfortunatelly my searches in the archives were useless.
 Well, I have some objects called after a name that has a number attached to
it,
 varying. Let's say I have:
 > ls
   poly1 poly2 poly3 poly4 poly5 poly6 ...
 
 I would like to access these objects using a for(), in which I could do
something like paste("poly",i,sep=''). For i = 4, for instance
I get
 > paste("poly",4,=sep'')
 [1] "poly8"
 Which is a string. What command should I use to 'access' the object
named
by this string, ir order to do some useful things, like changing its value?

Thank you,

--

Have you considered:

 > poly1 <- 1
 > get("poly1")
[1] 1
 >

hth.  spencer graves

Fernando Henrique Ferraz Pereira da Rosa wrote:
>  Hi, my doubt is very simple. I'm sure I've seen someone using
something
> like this before, but unfortunatelly my searches in the archives were
useless.
>  Well, I have some objects called after a name that has a number attached
to
> it,
>  varying. Let's say I have:
>  > ls
>    poly1 poly2 poly3 poly4 poly5 poly6 ...
>  
>  I would like to access these objects using a for(), in which I could do
> something like paste("poly",i,sep=''). For i = 4, for
instance I get
>  > paste("poly",4,=sep'')
>  [1] "poly8"
>  Which is a string. What command should I use to 'access' the
object named
> by this string, ir order to do some useful things, like changing its value?
> 
> Thank you,
> 
> --
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help

This was discussed in 

Date: 	1/06/2003 06:00:32
Subject: 	Re: [R] parse on left hand side of R assignment

On Sat, 31 May 2003, Paul E. Johnson wrote:
> I keep finding myself in a situation where I want to calculate a 
> variable name and then use it on the left hand side of an assignment. 
> For example
> 
> iteration <- 1
> varName <- paste("run",iteration,sep="")
> myList$parse(text=varName) <- aColumn
> 
> I want to take some existing variable  "aColumn" and use the name
> "varName" name for it and put it into a list "myList". 
That use fails
> with this error:
.... Snip 

For a data frame you could use

mydf[paste("run",iteration,sep="")] <- aColumn

and for a list or a data frame

Robject[[paste("run",iteration,sep="")]] <- aColumn

================================================I don't remember if there
was any more interesting discussion in the thread.

HTH
Edith

Edith Hodgen
Statistician and Data Manager
New Zealand Council for Educational Research
Phone: +64-4-384 7939 x 812
Fax:      +64-4-384 7933
edith.hodgen at nzcer.org.nz

           Web site http://www.nzcer.org.nz
>>> Fernando Henrique Ferraz Pereira da Rosa <mentus at gmx.de>
17/06/2003 13:43:42 >>>
 Hi, my doubt is very simple. I'm sure I've seen someone using something
like this before, but unfortunatelly my searches in the archives were useless.
 Well, I have some objects called after a name that has a number attached to
it,
 varying. Let's say I have:
 > ls
   poly1 poly2 poly3 poly4 poly5 poly6 ...
 
 I would like to access these objects using a for(), in which I could do
something like paste("poly",i,sep=''). For i = 4, for instance
I get
 > paste("poly",4,=sep'')
 [1] "poly8"
 Which is a string. What command should I use to 'access' the object
named
by this string, ir order to do some useful things, like changing its value?

Thank you,

--

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