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: > 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: > 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: wantia at ifi.unizh.ch
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. -- 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: r-help-bounces at stat.math.ethz.ch > [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Jan Wantia > Sent: Monday, December 13, 2004 8:00 AM > To: r-help at stat.math.ethz.ch > 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 $mean in one plot? For a matrix, mat[,2] > would give me > the whole second column, but > ALL[[]][[2]] > does not return all the second components. > > I feel that 'lapply' might help me here, but I could not figure out > exactly how to use it, and it always comes down to the > problem of how to > correctly address the components in the sublists. > > Or is there maybe a smarter way to do that instead of using a > list of lists? > > Any hint would be warmly appreciated! > > Jan > (R 2.0.1 on windows XP) > > -- > > ______________________________________________________ > > Jan Wantia > Deptartment of Informatics, University of Zurich > Andreasstr. 15 > CH 8050 Zurich > Switzerland > > Tel.: +41 (0) 1 635 4315 > Fax: +41 (0) 1 635 45 07 > email: wantia at ifi.unizh.ch > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html >
james.holtman@convergys.com
2004-Dec-13 16:46 UTC
[R] lists within a list / data-structure problem
construct you list in the loop:
x.all <- list() # initialize
for (i in 1:limit){
.......
x.all[[i]] <- result.list
}
now you want to name them, e.g., run1 ....
names(x.all) <- paste('run', seq(length(x.all)), sep='')
To access, you can do x.all$run1$Dom
To extract all the 'Dom's
lapply(x.all, function(x) x$Dom)
HTH
__________________________________________________________
James Holtman "What is the problem you are trying to solve?"
Executive Technical Consultant -- Office of Technology, Convergys
james.holtman at convergys.com
+1 (513) 723-2929
Jan Wantia
<wantia at ifi.unizh.ch> To: r-help at
stat.math.ethz.ch
Sent by: cc:
r-help-bounces at stat.m Subject: [R] lists within
a list / data-structure problem
ath.ethz.ch
12/13/2004 10:59
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:
> 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:
> 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: wantia at ifi.unizh.ch
______________________________________________
R-help at stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html