R help - Sep 2010 - adding list to data.frame iteratively

Hi,

I have a preallocated dataframe to which I have to add a list whose vectors will
become rows in the dataframe. This is done iteratively. How can I do this?
I'm dealing with very large numbers...list of 1000 vectors to a dataframe of
200000 iteratively

for e.g.
my list is as follows

ll<-list(c("1","2","3"),c("2","3","4"))

I have to add this to a dataframe
dd<-data.frame(matrix(nrow=10,ncol=3))

so that I get
1 2 3
2 3 4
etc.
	[[alternative HTML version deleted]]

>
ll<-list(c("1","2","3"),c("2","3","4"))
> ll
[[1]]
[1] "1" "2" "3"

[[2]]
[1] "2" "3" "4"
> dd<-data.frame(matrix(nrow=10,ncol=3)) 
> dd
   X1 X2 X3
1  NA NA NA
2  NA NA NA
3  NA NA NA
4  NA NA NA
5  NA NA NA
6  NA NA NA
7  NA NA NA
8  NA NA NA
9  NA NA NA
10 NA NA NA
> dd[1,]<-ll[[1]]
> dd
     X1   X2   X3
1     1    2    3
2  <NA> <NA> <NA>
3  <NA> <NA> <NA>
4  <NA> <NA> <NA>
5  <NA> <NA> <NA>
6  <NA> <NA> <NA>
7  <NA> <NA> <NA>
8  <NA> <NA> <NA>
9  <NA> <NA> <NA>
10 <NA> <NA> <NA>
> dd[2,]<-ll[[2]]
> dd
     X1   X2   X3
1     1    2    3
2     2    3    4
3  <NA> <NA> <NA>
4  <NA> <NA> <NA>
5  <NA> <NA> <NA>
6  <NA> <NA> <NA>
7  <NA> <NA> <NA>
8  <NA> <NA> <NA>
9  <NA> <NA> <NA>
10 <NA> <NA> <NA>

you could easily put this into a for loop such that
dd[i,]<-ll[[i]]
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Hi,

This is not exactly the same, but there was a recent thread on
rbind()ing dataframes from a list:

http://r.789695.n4.nabble.com/Please-explain-do-call-in-this-context-or-critique-to-stack-this-list-faster-td2526908.html

Given that, I wonder if this would work for you:

ll <-
list(c("1","2","3"),c("2","3","4"))
dd <- data.frame(matrix(nrow=10,ncol=3))
# rbind() each element of the list together into a data frame
temp <- as.data.frame(do.call("rbind", ll), stringsAsFactors =
FALSE)
# assign that dataframe to whichever rows of dd you want
dd[1:2, ] <- temp
# print to screen
dd

Just a thought,

Josh

On Tue, Sep 7, 2010 at 11:17 PM, rajeshj at cse.iitm.ac.in
<rajeshj at cse.iitm.ac.in> wrote:
>
> Hi,
>
> I have a preallocated dataframe to which I have to add a list whose vectors
will become rows in the dataframe. This is done iteratively. How can I do this?
> I'm dealing with very large numbers...list of 1000 vectors to a
dataframe of 200000 iteratively
>
> for e.g.
> my list is as follows
>
>
ll<-list(c("1","2","3"),c("2","3","4"))
>
> I have to add this to a dataframe
> dd<-data.frame(matrix(nrow=10,ncol=3))
>
> so that I get
> 1 2 3
> 2 3 4
> etc.
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>


-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/

Why don't you read the answers to your stackoverflow question?
http://stackoverflow.com/questions/3665885/adding-a-list-of-vectors-to-a-data-frame-in-r/3667753

Hadley

On Wed, Sep 8, 2010 at 1:17 AM, rajeshj at cse.iitm.ac.in
<rajeshj at cse.iitm.ac.in> wrote:
>
> Hi,
>
> I have a preallocated dataframe to which I have to add a list whose vectors
will become rows in the dataframe. This is done iteratively. How can I do this?
> I'm dealing with very large numbers...list of 1000 vectors to a
dataframe of 200000 iteratively
>
> for e.g.
> my list is as follows
>
>
ll<-list(c("1","2","3"),c("2","3","4"))
>
> I have to add this to a dataframe
> dd<-data.frame(matrix(nrow=10,ncol=3))
>
> so that I get
> 1 2 3
> 2 3 4
> etc.
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>


-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/