[R] Give me all operator
Joshua Wiley
jwiley.psych at gmail.com
Wed Nov 17 16:53:54 CET 2010
MyStruct <- list(list(CRmap = rnorm(50), xy = 1:50), list(CRmap =
rnorm(50), xy = 51:100))
I wonder if it would be possible to extend indexing to accept lists.
For example:
MyStruct[[c(1, 2)]] extracts level1[1] and level2[2], so if the vector
was a list, perhaps
MyStruct[[list(c(1, 2), 2)]] ## level1[1:2], level2[2]
In any case, I do not see a way presently that avoids lappy, but
within that limitation, this is slightly simpler:
lapply(MyStruct, `[`, "xy")
Josh
On Wed, Nov 17, 2010 at 6:56 AM, Ivan Calandra
<ivan.calandra at uni-hamburg.de> wrote:
> I understand now!
> But I don't know of any easy way to do it.
>
> You would expect that something like these would work:
> Mystruct[[1:2]][["xy"]] ## but error: subscript out of bounds, which makes
> sense because "[[" accept only a single subscript
> Mystruct[1:2][["xy"]] ## but NULL, which makes sense because "[" keeps
> the upper elements, not only what is within Mystruct[1] and Mystruct[2] (not
> sure I've stated right, but I hope you understand).
>
> I usually prefer using "[[" or "[" instead of "$" because you can use
> indexes, which is better to vectorize or loop.
>
> So the only solution I've found (maybe someone here might give us a better
> answer) is:
> lapply(Mystruct, FUN=subset, select=xy)
> or
> lapply(Mystruct, FUN=subset, subset=whatever, select=xy)
> if you also want to subset some specific rows
>
> HTH,
> Ivan
>
>
>
> Le 11/17/2010 15:26, Alaios a écrit :
>>
>> It seems that I am confusing something:
>>
>> List of 50
>> $ :List of 2
>> ..$ CRmap: logi [1:100, 1:100] NA NA NA NA NA NA ...
>> ..$ xy : num [1:2] 21 11
>> $ :List of 2
>> ..$ CRmap: logi [1:100, 1:100] NA NA NA NA NA NA ...
>> ..$ xy : num [1:2] 80 68
>>
>>
>>
>> --- On *Wed, 11/17/10, Ivan Calandra /<ivan.calandra at uni-hamburg.de>/*
>> wrote:
>>
>>
>> From: Ivan Calandra <ivan.calandra at uni-hamburg.de>
>> Subject: Re: [R] Give me all operator
>> To: r-help at r-project.org
>> Date: Wednesday, November 17, 2010, 2:05 PM
>>
>> Well, without knowing what is the structure of Mystruct.Map and
>> Mystruct.xy, it's really difficult to know how to help you.
>> And what is Mystruct by the way!?
>> Could you send us the output from dput(your_objects) and/or
>> str(your_objects)?
>>
>> I think you're really confused about the structure of your
>> objects. You
>> probably need to read more stuff about that!
>>
>> Ivan
>>
>> Le 11/17/2010 14:56, Alaios a écrit :
>> > Thanks a lot for your helpful answer.
>> > In my case now I have implemented some "struct" with the following
>> > structure
>> > Mystruct.Map
>> > Mystruct.xy
>> >
>> > If I do Mystruct[2].$xy I get correctly the xy values of the
>> second item.
>> >
>> > I want now to print all the $xy fields of the Mystruct[[]]
>> > I tried
>> > Mystruct[data.frame(a=1:5)]]$xy which returns the following message:
>> >
>> > invalid subscript type 'list'
>> >
>> >
>> > I would like to thank you again for your support
>> > Regards
>> > Alex
>> >
>> > --- On *Wed, 11/17/10, Ivan Calandra
>> /<ivan.calandra at uni-hamburg.de
>> </mc/compose?to=ivan.calandra at uni-hamburg.de>>/*
>> > wrote:
>> >
>> >
>> > From: Ivan Calandra <ivan.calandra at uni-hamburg.de
>> </mc/compose?to=ivan.calandra at uni-hamburg.de>>
>> > Subject: Re: [R] Give me all operator
>> > To: r-help at r-project.org </mc/compose?to=r-help at r-project.org>
>> > Date: Wednesday, November 17, 2010, 1:44 PM
>> >
>> > Hi Alex,
>> >
>> > Is that what you're looking for:
>> > > df <- data.frame(a=LETTERS[1:5], b=rnorm(5))
>> > > df
>> > a b
>> > 1 A -0.2401323
>> > 2 B -0.9414998
>> > 3 C 0.4289836
>> > 4 D 1.9802749
>> > 5 E -0.6993612
>> > > df[3,2]
>> > [1] 0.4289836
>> > > df[3,]
>> > a b
>> > 3 C 0.4289836
>> > > df[,2]
>> > [1] -0.2401323 -0.9414998 0.4289836 1.9802749 -0.6993612
>> > > df[,2, drop=FALSE]
>> > b
>> > 1 -0.2401323
>> > 2 -0.9414998
>> > 3 0.4289836
>> > 4 1.9802749
>> > 5 -0.6993612
>> >
>> > See ?"[" for help. In short, in R you use "[", not brackets
>> as in
>> > matlab
>> > (from your example, I've never used it). You don't need the
>> ":", you
>> > just don't write anything in R.
>> >
>> > Ivan
>> >
>> > Le 11/17/2010 14:34, Alaios a écrit :
>> > > Hello is there in R any operator that give you all the data of a
>> > matrix
>> > > for example in matlab
>> > >
>> > > x(2,3) returns the 2ndth row and 3rdth column
>> > > x(2,:) returns all the columns of the 2nd row.
>> > >
>> > > In R now I would like to print all the
>> > >
>> > > CRagent[[i]][2]
>> > >
>> > >
>> > > CRagent[[:]][2] doesnot work of course. Other option is to
>> > make a loop with an index i that spans from 1:last element of
>> > CRagent[[]] but this is not that optimal.
>> > >
>> > > I would like to thank you in aavance for your help
>> > > Best Regards
>> > > Alex
>> > >
>> > >
>> > >
>> > >
>> > > [[alternative HTML version deleted]]
>> > >
>> > >
>> > >
>> > > ______________________________________________
>> > > R-help at r-project.org </mc/compose?to=R-help at r-project.org>
>> </mc/compose?to=R-help at r-project.org
>> </mc/compose?to=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.
>> >
>> > --
>> > Ivan CALANDRA
>> > PhD Student
>> > University of Hamburg
>> > Biozentrum Grindel und Zoologisches Museum
>> > Abt. Säugetiere
>> > Martin-Luther-King-Platz 3
>> > D-20146 Hamburg, GERMANY
>> > +49(0)40 42838 6231
>> > ivan.calandra at uni-hamburg.de
>> </mc/compose?to=ivan.calandra at uni-hamburg.de>
>> > </mc/compose?to=ivan.calandra at uni-hamburg.de
>> </mc/compose?to=ivan.calandra at uni-hamburg.de>>
>> >
>> > **********
>> > http://www.for771.uni-bonn.de
>> > http://webapp5.rrz.uni-hamburg.de/mammals/eng/mitarbeiter.php
>> >
>> > ______________________________________________
>> > R-help at r-project.org </mc/compose?to=R-help at r-project.org>
>> </mc/compose?to=R-help at r-project.org
>> </mc/compose?to=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.
>> >
>> >
>>
>> -- Ivan CALANDRA
>> PhD Student
>> University of Hamburg
>> Biozentrum Grindel und Zoologisches Museum
>> Abt. Säugetiere
>> Martin-Luther-King-Platz 3
>> D-20146 Hamburg, GERMANY
>> +49(0)40 42838 6231
>> ivan.calandra at uni-hamburg.de
>> </mc/compose?to=ivan.calandra at uni-hamburg.de>
>>
>> **********
>> http://www.for771.uni-bonn.de
>> http://webapp5.rrz.uni-hamburg.de/mammals/eng/mitarbeiter.php
>>
>> ______________________________________________
>> R-help at r-project.org </mc/compose?to=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.
>>
>>
>
> --
> Ivan CALANDRA
> PhD Student
> University of Hamburg
> Biozentrum Grindel und Zoologisches Museum
> Abt. Säugetiere
> Martin-Luther-King-Platz 3
> D-20146 Hamburg, GERMANY
> +49(0)40 42838 6231
> ivan.calandra at uni-hamburg.de
>
> **********
> http://www.for771.uni-bonn.de
> http://webapp5.rrz.uni-hamburg.de/mammals/eng/mitarbeiter.php
>
> ______________________________________________
> 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/
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