R help - Jan 2009 - List of Lists

Dear All;

Is it possible to create a list of lists (I am sure it is) along these
lines;

I have a dataframe data02 that holds a lot of information, and the first
column is ³date²

I have a list of dates in;

data03<-c(date1,.....,daten)

And would like to create a list;

data04 <- subset(data02, date == data03[1,])

Ie. data04 holds the data from data02 that matches a date in data03

How do I create a list data04 that instead rolls through all the elements of
data03 and each element of data04 is a list

Regards

Glenn

	[[alternative HTML version deleted]]

See if one of %in% or match gets your further.

 > 1:10 %in% c(1,3,5,9)
  [1]  TRUE FALSE  TRUE FALSE  TRUE FALSE FALSE FALSE  TRUE FALSE
 > match(c(1,3,5,9), 1:10)
[1] 1 3 5 9
 > match(c(1,3,5,9), 10:1)
[1] 10  8  6  2

date03 as offered was not a list, but a vector.

date04 <- date02[which(date02$date %in% date3), ]  # might work,  
nothing to test it on

If you only want the column of matching dates and not all the rows  
that have matching dates then this might work:
date04 <- date02[which(date02$date %in% date3), "date" ]

 From you incorrect use of the term "list" (in the context of R,  
anyway), I am guessing that you don't really want lists but rather  
subsets of data.frames. Vector and list are not interchangeable terms  
in these parts.


-- 
David Winsemius

On Jan 14, 2009, at 2:53 PM, glenn wrote:
> Dear All;
>
> Is it possible to create a list of lists (I am sure it is) along these
> lines;
>
> I have a dataframe data02 that holds a lot of information, and the  
> first
> column is ?date?
>
> I have a list of dates in;
>
> data03<-c(date1,.....,daten)
>
> And would like to create a list;
>
> data04 <- subset(data02, date == data03[1,])
>
> Ie. data04 holds the data from data02 that matches a date in data03
>
> How do I create a list data04 that instead rolls through all the  
> elements of
> data03 and each element of data04 is a list
>
> Regards
>
> Glenn
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

On Wed, Jan 14, 2009 at 1:53 PM, glenn <g1enn.roberts at btinternet.com>
wrote:
> Dear All;
>
> Is it possible to create a list of lists (I am sure it is) along these
> lines;
>
> I have a dataframe data02 that holds a lot of information, and the first
> column is ?date?
>
> I have a list of dates in;
>
> data03<-c(date1,.....,daten)
>
> And would like to create a list;
>
> data04 <- subset(data02, date == data03[1,])
>
> Ie. data04 holds the data from data02 that matches a date in data03
>
> How do I create a list data04 that instead rolls through all the elements
of
> data03 and each element of data04 is a list
Have a look at ?split.

Hadley

-- 
http://had.co.nz/