[R] storing element number of a list in a column data frame

[Massimo Bressan]

yes, I like this: a very elegant and neat solution (in my very umble 
opinion)
sometime is so difficult to me to think of a solution in such a simple 
and effective terms: less is more!
thank you
max


Il 03/10/2013 17:12, David Carlson ha scritto:
> Try this
>
>> i=which(!sapply(mytest, is.null))
>> n=do.call(rbind, mytest[i])
>> mydf <- data.frame(i, n)
>> mydf
>    i  n
> 1 1 45
> 2 3 18
> 3 5 99
>
> -------------------------------------
> David L Carlson
> Associate Professor of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
> -----Original Message-----
> From: r-help-bounces at r-project.org
> [mailto:r-help-bounces at r-project.org] On Behalf Of Massimo
> Bressan
> Sent: Thursday, October 3, 2013 9:42 AM
> To: r-help at r-project.org
> Subject: [R] storing element number of a list in a column data
> frame
>
> #let's suppose I have a list like this
>
> mytest<-list(45, NULL, 18, NULL, 99)
>
> #to note that this is just an amended example because in fact
>
> #I'm dealing with a long list (more than 400 elements)
>
> #with no evident pattern of the NULL values
>
> #I want to end up with a data frame like the following
>
> data.frame(i=c(1,3,5), n=c(45,18,99))
>
> #i.e. a data frame storing in
>
> #column i the number of corresponding element list
>
> #column n the unique component of that element
>
> #I've been trying with
>
> do.call(rbind, mytest)
>
> #or
>
> do.call(rbind.data.frame, mytest)
>
> #but this approach is not properly achieving the desired result
>
> #now I'm in trouble on how to store each element number of the
> list in
> the first column data frame
>
> #any help for this?
>
> #thanks
>
>
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>
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