R help - May 2014 - variable length lisin in data frame

Dear Group,
I have data like the following

id   contacts_list   number of contacts
---------------------------------------------------
1   3 4                               2
2   1 3 4                            3
3    4 2 1                           3
4    1                                1
------------------------------------------------------


can you kindly please sugest a data type in R to use for it?
i thought about data frame that consists of a  list element. but  lists are not
in  the same length, any  solutions?
thanks in advance
RAE
 		 	   		  
	[[alternative HTML version deleted]]

On 10/05/2014, 7:46 AM, Ragia Ibrahim wrote:
> Dear Group,
> I have data like the following
>
> id   contacts_list   number of contacts
> ---------------------------------------------------
> 1   3 4                               2
> 2   1 3 4                            3
> 3    4 2 1                           3
> 4    1                                1
> ------------------------------------------------------
>
>
> can you kindly please sugest a data type in R to use for it?
> i thought about data frame that consists of a  list element. but  lists are
not in  the same length, any  solutions?
You can use a dataframe, but the data.frame function gets confused by 
the contacts_list, so you need to set it up in two steps, e.g.

d <- data.frame(id=1:4,  no.contacts=c(2,3,3,1))
d$contacts_list <- list(3:4, c(1,3,4), c(4,2,1), 1 )

Other dataframe functions (e.g. printing, indexing, etc.) should work:

 > d
   id no.contacts contacts_list
1  1           2          3, 4
2  2           3       1, 3, 4
3  3           3       4, 2, 1
4  4           1             1

 > d[2,]
   id no.contacts contacts_list
2  2           3       1, 3, 4

A slightly confusing bit is that if you pick out a single element of 
column 3 you'll get a list containing it:

 > d[2,3]
[[1]]
[1] 1 3 4

so you should use the double bracket list-indexing style:

 > d[[2,3]]
[1] 1 3 4

Duncan Murdoch

I think it will depend on how you plan to use the data. Again in my
opinion, I think the simplest most natural storage structure in the
context of R would be a nested list:

mydat <- list(
  list(contacts=c(3,4), ncon=2),
  list(contacts=c(1,3,4), ncon=3),
  list(contacts=c(4,2,1), ncon=3),
  list(contacts=1, ncon=1)
  )

## if the id values are not sequential integers, then you would also need
names(mydat) <- {whatever the id values are}

Depending on subsequent processing, it might not be necessary to store the
number of contacts, because it can easily be calculated whenever needed.
In which case the structure could be simpler:

mydat <- list( c(3,4), c(1,3,4), c(4,2,1), 1 )
names(mydat) <- {whatever the id values are}


Even though a data frame can be used, as Duncan and arun have shown, a
data frame does not seem natural to me, given that the number of contacts
is not the same for all ids.

It may also depend on where the data is coming from and how much there is
of it.

-Don

-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 5/10/14 4:46 AM, "Ragia Ibrahim" <ragia11 at hotmail.com>
wrote:
>Dear Group,
>I have data like the following
>
>id   contacts_list   number of contacts
>---------------------------------------------------
>1   3 4                               2
>2   1 3 4                            3
>3    4 2 1                           3
>4    1                                1
>------------------------------------------------------
>
>
>can you kindly please sugest a data type in R to use for it?
>i thought about data frame that consists of a  list element. but  lists
>are not in  the same length, any  solutions?
>thanks in advance
>RAE
> 		 	   		  
>	[[alternative HTML version deleted]]
>
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