Dear list, I have two lists: one with data and one with TRUE/FALSE values for data I want to further analyze (see example below). I have been able to use a for loop to extract the data that I want to keep, but think that there probably exists a way to do it without a loop. Any ideas? #sample data set.seed(100) example = list(letters[1:10], letters[1:10], letters[1:10]) ind = list(as.logical(sample(0:1, 10, rep=TRUE)), as.logical(sample(0:1, 10, rep=TRUE)), as.logical(sample(0:1, 10, rep=TRUE)), as.logical(sample(0:1, 10, rep=TRUE))) #loop method for (i in 1:length(example)) print(example[[i]][ind[[i]]]) #result [1] "c" "g" "i" [1] "a" "b" "e" "f" "j" [1] "a" "b" "c" "d" "g" "h" "i" Thank you for the help. Greg -- Greg Hirson ghirson at ucdavis.edu Graduate Student Agricultural and Environmental Chemistry 1106 Robert Mondavi Institute North One Shields Avenue Davis, CA 95616
Your example has one more element in 'ind' than 'example' and that is what causes the error, but this should be close.> #sample data > set.seed(100) > example = list(letters[1:10], letters[1:10], letters[1:10]) > ind = list(as.logical(sample(0:1, 10, rep=TRUE)),+ as.logical(sample(0:1, 10, rep=TRUE)), + as.logical(sample(0:1, 10, rep=TRUE)), + as.logical(sample(0:1, 10, rep=TRUE)))> > mapply(function(a,b)a[b], example, ind)[[1]] [1] "c" "g" "i" [[2]] [1] "a" "b" "e" "f" "j" [[3]] [1] "a" "b" "c" "d" "g" "h" "i" [[4]] [1] "b" "d" "e" "f" "h" "i" Warning message: In mapply(function(a, b) a[b], example, ind) : longer argument not a multiple of length of shorter>On Fri, Jun 26, 2009 at 2:27 PM, Greg Hirson <ghirson@ucdavis.edu> wrote:> Dear list, > > I have two lists: one with data and one with TRUE/FALSE values for data I > want to further analyze (see example below). I have been able to use a for > loop to extract the data that I want to keep, but think that there probably > exists a way to do it without a loop. Any ideas? > > #sample data > set.seed(100) > example = list(letters[1:10], letters[1:10], letters[1:10]) > ind = list(as.logical(sample(0:1, 10, rep=TRUE)), as.logical(sample(0:1, > 10, rep=TRUE)), as.logical(sample(0:1, 10, rep=TRUE)), > as.logical(sample(0:1, 10, rep=TRUE))) > > #loop method > for (i in 1:length(example)) print(example[[i]][ind[[i]]]) > > #result > [1] "c" "g" "i" > [1] "a" "b" "e" "f" "j" > [1] "a" "b" "c" "d" "g" "h" "i" > > > Thank you for the help. > > Greg > > -- > Greg Hirson > ghirson@ucdavis.edu > > Graduate Student > Agricultural and Environmental Chemistry > > 1106 Robert Mondavi Institute North > One Shields Avenue > Davis, CA 95616 > > ______________________________________________ > R-help@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<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. >-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? [[alternative HTML version deleted]]
You have four elements in ind and three elements in example, then, try this
mapply('[', example, ind[1:3])
On Fri, Jun 26, 2009 at 3:27 PM, Greg Hirson <ghirson@ucdavis.edu> wrote:
> Dear list,
>
> I have two lists: one with data and one with TRUE/FALSE values for data I
> want to further analyze (see example below). I have been able to use a for
> loop to extract the data that I want to keep, but think that there probably
> exists a way to do it without a loop. Any ideas?
>
> #sample data
> set.seed(100)
> example = list(letters[1:10], letters[1:10], letters[1:10])
> ind = list(as.logical(sample(0:1, 10, rep=TRUE)), as.logical(sample(0:1,
> 10, rep=TRUE)), as.logical(sample(0:1, 10, rep=TRUE)),
> as.logical(sample(0:1, 10, rep=TRUE)))
>
> #loop method
> for (i in 1:length(example)) print(example[[i]][ind[[i]]])
>
> #result
> [1] "c" "g" "i"
> [1] "a" "b" "e" "f" "j"
> [1] "a" "b" "c" "d" "g"
"h" "i"
>
>
> Thank you for the help.
>
> Greg
>
> --
> Greg Hirson
> ghirson@ucdavis.edu
>
> Graduate Student
> Agricultural and Environmental Chemistry
>
> 1106 Robert Mondavi Institute North
> One Shields Avenue
> Davis, CA 95616
>
> ______________________________________________
> R-help@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.
>
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
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