Berton Gunter wrote:
Jan:
One thing to keep in mind: A list is vector. So vector-type operations like
c(), "[", etc. work on lists, too (but be careful). Some comments inline
below that I hope will be helpful. A good reference on the S language is
V&R's S PROGRAMMING, which I recommend highly.
You can also have a matrix of lists.
Kjetil
-- Bert Gunter
Genentech Non-Clinical Statistics
South San Francisco, CA
"The business of the statistician is to catalyze the scientific learning
process." - George E. P. Box
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jan Wantia
Sent: Monday, December 13, 2004 8:00 AM
To: [EMAIL PROTECTED]
Subject: [R] lists within a list / data-structure problem
Dear all,
this is a rather basic question; i am not sure how to
structure my data
well:
I want to extraxt various measures from my raw-data. These
measures are
of different sizes, so I decided to store them in a list, like:
run1 <- list(Dom = (my_vector), mean = (my_single_number))
I can do that in a for loop for 40 runs, ending up with 40
lists: run1,
run2, ..., run40.
To have all the measurements neatly together I thought of
making another
list, containing 40 sub-lists:
As you found, this is clumsy. The usual way to do this is to put the results
into a *single* list as follows:
## Contruct the empty list with 40 components:
out<-vector("list", 40)
### loop
... ## do the calculations
out[[i]] <- list(Dom = yourvec,mean=yournumb)
...
> ALL <- list(run1, run2,..., run40)
> ALL
[[1]]
[[1]]$Dom
[1] "my_vector"
[[1]]$mean
[1] "my_single_number"
[[2]]
[[2]]$Dom
[1] "my_vector"
[[2]]$mean
[1] "my_single_number"
...
1) This may be a bit clumsy as I have to type all the sub-list's names
in by hand in order to produce my ALL-list: Is there a better way?
2) I have problems of addressing the data now. I can easily access any
single value; for example, for the second component of the
second sub- list:
out[[i]] is the ith component of the list, i.e. the ith 2 component list
containing the result of the ith loop. So out[[i]][[1]] is yourvec for the
ith loop and out[[i]][[2]] is yournumb. These can be abbreciated as
out[[c(i,1]] and out[[c(i,2)]]
> ALL[[2]][[2]]
[1] "my_single_number",
but: how could I get the second component of all sub-lists,
to plot, for
example, all the $mean in one plot? For a matrix, mat[,2]
would give me
the whole second column, but
ALL[[]][[2]]
does not return all the second components.
I feel that 'lapply' might help me here, but I could not figure out
exactly how to use it, and it always comes down to the
problem of how to
correctly address the components in the sublists.
Or is there maybe a smarter way to do that instead of using a
list of lists?
Any hint would be warmly appreciated!
Jan
(R 2.0.1 on windows XP)
--
______________________________________________________
Jan Wantia
Deptartment of Informatics, University of Zurich
Andreasstr. 15
CH 8050 Zurich
Switzerland
Tel.: +41 (0) 1 635 4315
Fax: +41 (0) 1 635 45 07
email: [EMAIL PROTECTED]
______________________________________________
[EMAIL PROTECTED] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
______________________________________________
[EMAIL PROTECTED] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
--
Kjetil Halvorsen.
Peace is the most effective weapon of mass construction.
-- Mahdi Elmandjra
______________________________________________
[EMAIL PROTECTED] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
