add vectors to multiple objects

Hi everyone,

I try to add many vectors (L1,L2,L3....) to many list objects  
(a.list, b.list....) in a workspace. Somethings like below, but it  
is not working. Any suggestions will be appreciated. Best, John

lf=ls(pattern=".lst")

 for (x in listfiles) {
    dat=read.delim(x,header=F)

Presumably that would fail since 'listfiles' has not been defined. did  
you mean 'lf'? If you did,then wouldn't the second line overwrite all  
the early values of "dat" leaving only the last one?

Perhaps:
   datfils <- list()
   for (x in listfiles) {
     datfils[x] <- read.delim(x,header=F)

    for (i in 1: lf) {

And that would fail because 'lf' is a character vector, and it's not  
meaningful to specify such a range. Try instead:

      for (i in names(datfils[x]) ) {
#
# which will then iterate over the names of the files which are now  
also the names of the list elements

    assign(i$add,as.numeric(dat[,3]))

But since 'i' is a length-1 character vector, the expression `i$add`  
will be meaningless. The "$" operator does not do function calling in  
R unless you do fancy things with environments, and you cannot "sub- 
assign" in that manner, at least not with the assign() function.

Try instead:

     assign(i, as.numeric(datfils[x][,3]))
     names(i)[length(i)] <- "add"

Or:
      i <- transform(i, add=datfils[x][,3] )

  #or i$add=as.numeric(dat[,3]
    names(i)[names(i)=="add"]=substr(x,1,5)

I'm not sure these would be doing the same thing. What was your goal  
here?

    print (i[1:3,])
 }
}

David Winsemius, MD
Alameda, CA, USA

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Hi David,

Thanks for response, but my key question still remains unsolved.  
That is, how to add many vectors (L1,L2,L3....) to many list objects  
(a.list, b.list....) in a workspace?

listObjects=ls(pattern=".list") #for example,  a.list, b.list...


for (object in listObjects){

#how to sign vectors L1,L2,..Ln to each object (a.list, b.list...)


}

Any suggestions/comments/ideas will be appreciated.

Can we have code that creates these entities in the workspace? (That  
is what is meant as a reproducible example.)  I cannot tell whether  
there are already objects named "L1", "L2",... to which you wish to  
append the value of the objects found,  or  that you want to assign  
values to names that only exist as character vectors.

David.

>
> John
>
>
> From: David Winsemius <dwinsemius at comcast.net>
> To: John linux-user <johnlinuxuser at yahoo.com>
> Cc: "r-help at r-project.org" <r-help at r-project.org>
> Sent: Wednesday, August 1, 2012 7:21 PM
> Subject: Re: [R] add vectors to multiple objects
>
>
> On Aug 1, 2012, at 8:11 AM, John linux-user wrote:
>
> > Hi everyone,
> >
> > I try to add many vectors (L1,L2,L3....) to many list objects  
> (a.list, b.list....) in a workspace. Somethings like below, but it  
> is not working. Any suggestions will be appreciated. Best, John
> >
> > lf=ls(pattern=".lst")
> >
> >  for (x in listfiles) {
> >    dat=read.delim(x,header=F)
>
> Presumably that would fail since 'listfiles' has not been defined.  
> did you mean 'lf'? If you did,then wouldn't the second line  
> overwrite all the early values of "dat" leaving only the last one?
>
> Perhaps:
>   datfils <- list()
>   for (x in listfiles) {
>     datfils[x] <- read.delim(x,header=F)
>
>
> >
> >    for (i in 1: lf) {
>
> And that would fail because 'lf' is a character vector, and it's not  
> meaningful to specify such a range. Try instead:
>
>     for (i in names(datfils[x]) ) {
> #
> # which will then iterate over the names of the files which are now  
> also the names of the list elements
>
> >    assign(i$add,as.numeric(dat[,3]))
>
> But since 'i' is a length-1 character vector, the expression `i$add`  
> will be meaningless. The "$" operator does not do function calling  
> in R unless you do fancy things with environments, and you cannot  
> "sub-assign" in that manner, at least not with the assign() function.
>
> Try instead:
>
>     assign(i, as.numeric(datfils[x][,3]))
>     names(i)[length(i)] <- "add"
>
> Or:
>     i <- transform(i, add=datfils[x][,3] )
>
>
>
> >  #or i$add=as.numeric(dat[,3]
> >    names(i)[names(i)=="add"]=substr(x,1,5)
>
> I'm not sure these would be doing the same thing. What was your goal  
> here?
>
> >
> >    print (i[1:3,])
> >  }
> > }
>
>
> David Winsemius, MD
> Alameda, CA, USA
>
>
>

David Winsemius, MD
Alameda, CA, USA

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Maybe what I previously posted was not clear enough or something else. All vectors L1,L2.. and objects (e.g. a.list, b.list, c.list) already exit or easily to be created in a workspace. Do not worry about those. The key question is how to systematically append/assign these vectors to many objects (hundreds) in a loop without explicitly typing these object names one by one. Please refer to my code posted below to detail my question.  I really appreciate your ideas/suggestions. John

Like David, I find this still somewhat confusing, but perhaps this
will get you started:

a3 <- 1:4
b3 <- 6
c3 <- letters

a_new_thing <- do.call(list, lapply(ls(pattern = "3"), get))

old_thing <- list("cow")

a_longer_old_thing <- c(old_thing, a_new_thing)

adapt as needed.

Best,
Michael

On Fri, Aug 3, 2012 at 2:53 PM, John linux-user <johnlinuxuser at yahoo.com 

wrote:
Maybe what I previously posted was not clear enough or something  
else. All vectors L1,L2.. and objects (e.g. a.list, b.list, c.list)  
already exit or easily to be created in a workspace. Do not worry  
about those. The key question is how to systematically append/ 
assign these vectors to many objects (hundreds) in a loop without  
explicitly typing these object names one by one. Please refer to my  
code posted below to detail my question.  I really appreciate your  
ideas/suggestions. John

Like David, I find this still somewhat confusing, but perhaps this
will get you started:

a3 <- 1:4
b3 <- 6
c3 <- letters

a_new_thing <- do.call(list, lapply(ls(pattern = "3"), get))

old_thing <- list("cow")

a_longer_old_thing <- c(old_thing, a_new_thing)

adapt as needed.

Heh. Users of this should realize that Michael probably did this in  
clean session. If you run it with any other items in the workspace  
that have  "3" in their names they get wrapped up too. I had a 300  
line dataframe as well as a function whose values both got gathered up.

In the case where one needed to isolate a disjoint group of items, one  
might want to create an environment in which to segregate those items.  
the ls function can be directed to look in only one environment.

I wondered if this were the route intended:

for( i in seq_along(ls(patt=".lst") ) ) {
            assign( ls(patt=".lst")[i],  # the name of the i-th ".lst"- 
item
                    append(
                       sapply(ls(patt=".lst$"), get)[i],  # the  
original value
                       sapply(ls(patt="^L\\d"), get)[i] ) )} # the  
appended i-th "L"-value

I think it is far from optimal to have a loose collection of objects  
in the workspace. Much better to have them all in one list or an  
environment.

David Winsemius, MD
Alameda, CA, USA