R help - Jan 2008 - How to calculate the mean of all values in a list or dataframe

Hello all,

I've scoured the archives and google and I can't figure out how to
amalgamate a set of vectors of differing lengths in such a way as I can
calculate the mean easily.

The following dummy example contains vectors of length 1, but my data
has vectors of various lengths.

R> test = list(); for(i in 1:5) {test = append(test, i)}

R> test
[[1]]
[1] 1

[[2]]
[1] 2

[[3]]
[1] 3

[[4]]
[1] 4

[[5]]
[1] 5

R> mean(test)
[1] NA
Warning message:
argument is not numeric or logical: returning NA in: mean.default(test)

I need to be able to construct the structure in a loop, but it does not
really matter what type that structure is. I just want to be able to
boxplot() and mean() and other simple functions. Each index in the list
(as in the case above) can be considered a run of a test, the values in
that index the results of that run, which have different number of
elements. I would like the mean of all the values in all the runs.

What is the best type for collecting a set of numeric vectors of
differing lengths in a for loop for the most flexibility and ease of
using functions on the whole data or parts of it?

Thanks for your time,
B. Bogart

?unlist
mean(unlist(test)) 


Bert Gunter
Genentch Nonclinical Statistics


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
Behalf Of B. Bogart
Sent: Friday, January 11, 2008 11:29 AM
To: r-help at r-project.org
Subject: [R] How to calculate the mean of all values in a list or dataframe

Hello all,

I've scoured the archives and google and I can't figure out how to
amalgamate a set of vectors of differing lengths in such a way as I can
calculate the mean easily.

The following dummy example contains vectors of length 1, but my data
has vectors of various lengths.

R> test = list(); for(i in 1:5) {test = append(test, i)}

R> test
[[1]]
[1] 1

[[2]]
[1] 2

[[3]]
[1] 3

[[4]]
[1] 4

[[5]]
[1] 5

R> mean(test)
[1] NA
Warning message:
argument is not numeric or logical: returning NA in: mean.default(test)

I need to be able to construct the structure in a loop, but it does not
really matter what type that structure is. I just want to be able to
boxplot() and mean() and other simple functions. Each index in the list
(as in the case above) can be considered a run of a test, the values in
that index the results of that run, which have different number of
elements. I would like the mean of all the values in all the runs.

What is the best type for collecting a set of numeric vectors of
differing lengths in a for loop for the most flexibility and ease of
using functions on the whole data or parts of it?

Thanks for your time,
B. Bogart

______________________________________________
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.

?lapply in the case of a list.

test=list(a=1:5, b=1:4)
lapply(test, mean)


--- "B. Bogart" <bbogart at sfu.ca> wrote:
> Hello all,
> 
> I've scoured the archives and google and I can't
> figure out how to
> amalgamate a set of vectors of differing lengths in
> such a way as I can
> calculate the mean easily.
> 
> The following dummy example contains vectors of
> length 1, but my data
> has vectors of various lengths.
> 
> R> test = list(); for(i in 1:5) {test = append(test,
> i)}
> 
> R> test
> [[1]]
> [1] 1
> 
> [[2]]
> [1] 2
> 
> [[3]]
> [1] 3
> 
> [[4]]
> [1] 4
> 
> [[5]]
> [1] 5
> 
> R> mean(test)
> [1] NA
> Warning message:
> argument is not numeric or logical: returning NA in:
> mean.default(test)
> 
> I need to be able to construct the structure in a
> loop, but it does not
> really matter what type that structure is. I just
> want to be able to
> boxplot() and mean() and other simple functions.
> Each index in the list
> (as in the case above) can be considered a run of a
> test, the values in
> that index the results of that run, which have
> different number of
> elements. I would like the mean of all the values in
> all the runs.
> 
> What is the best type for collecting a set of
> numeric vectors of
> differing lengths in a for loop for the most
> flexibility and ease of
> using functions on the whole data or parts of it?
> 
> Thanks for your time,
> B. Bogart
> 
> ______________________________________________
> 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.
>