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

[David Carlson]

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


	[[alternative HTML version deleted]]

______________________________________________
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.