R help - May 2010 - getting a weighted average from a table

Hi,

I have a very simple request (I think).
I have a vector/array,

  > c <- c(1.3,1.2,1,3.3,3.3,5.1,1.1,1.2,0)

I produce a reverse sorted table/histogram with it,

  > t = rev(sort(table(c))
  > t
  c
  3.3 1.2 5.1 1.3 1.1   1   0 
    2   2   1   1   1   1   1 

I would now like to get the labels "3.3 1.2 5.1 1.3 1.1   1   0"
into its own vector and the # of counts "2   2   1   1   1   1   1"
so I can calculate weighted averages. So if I can get the labels into
a vector l and the counts into a vector n,

  l <- c(3.3,1.2,5.1,1.3,1.1,1,0);
  n <- c(2,2,1,1,1,1,1);

for(i=0;i<7;i++)
  total = l[i]*n[i]
total = total / sum(n)     <- this is the weight average

Hi,

I have a very simple request (I think).
I have a vector/array,

  > c <- c(1.3,1.2,1,3.3,3.3,5.1,1.1,1.2,0)

I produce a reverse sorted table/histogram with it,

  > t = rev(sort(table(c))
  > t
  c
  3.3 1.2 5.1 1.3 1.1   1   0 
    2   2   1   1   1   1   1 

I would now like to get the labels "3.3 1.2 5.1 1.3 1.1   1   0"
into its own vector and the # of counts "2   2   1   1   1   1   1"
so I can calculate weighted averages. So if I can get the labels into
a vector l and the counts into a vector n,

  l <- c(3.3,1.2,5.1,1.3,1.1,1,0);
  n <- c(2,2,1,1,1,1,1);

for(i=0;i<7;i++)
  total = l[i]*n[i]
total = total / sum(n)     <- this is the weight average

On May 7, 2010, at 9:42 AM, SHANE MILLER, BLOOMBERG/ 731 LEXIN wrote:
> Hi,
>
> I have a very simple request (I think).
> I have a vector/array,
>
>> c <- c(1.3,1.2,1,3.3,3.3,5.1,1.1,1.2,0)
>
> I produce a reverse sorted table/histogram with it,
>
>> t = rev(sort(table(c))
>> t
>  c
>  3.3 1.2 5.1 1.3 1.1   1   0
>    2   2   1   1   1   1   1
>
> I would now like to get the labels "3.3 1.2 5.1 1.3 1.1   1   0"
> into its own vector and the # of counts "2   2   1   1   1   1  
1"
 > names(t)
[1] "3.3" "1.2" "5.1" "1.3"
"1.1" "1"   "0"
 > as.numeric(names(t))
[1] 3.3 1.2 5.1 1.3 1.1 1.0 0.0
 > unname(t)
[1] 2 2 1 1 1 1 1

> so I can calculate weighted averages. So if I can get the labels into
> a vector l and the counts into a vector n,
>
>  l <- c(3.3,1.2,5.1,1.3,1.1,1,0);
>  n <- c(2,2,1,1,1,1,1);
>
> for(i=0;i<7;i++)
>  total = l[i]*n[i]
> total = total / sum(n)     <- this is the weight average
> ______________________________________________
> 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.
David Winsemius, MD
West Hartford, CT

dat = c(1.3,1.2,1,3.3,3.3,5.1,1.1,1.2,0)
tt = table(dat)
sum(as.numeric(names(tt))*tt)/ sum(tt)

 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu


On Fri, 7 May 2010, SHANE MILLER, BLOOMBERG/ 731 LEXIN wrote:
> Hi,
>
> I have a very simple request (I think).
> I have a vector/array,
>
>  > c <- c(1.3,1.2,1,3.3,3.3,5.1,1.1,1.2,0)
>
> I produce a reverse sorted table/histogram with it,
>
>  > t = rev(sort(table(c))
>  > t
>  c
>  3.3 1.2 5.1 1.3 1.1   1   0
>    2   2   1   1   1   1   1
>
> I would now like to get the labels "3.3 1.2 5.1 1.3 1.1   1   0"
> into its own vector and the # of counts "2   2   1   1   1   1  
1"
> so I can calculate weighted averages. So if I can get the labels into
> a vector l and the counts into a vector n,
>
>  l <- c(3.3,1.2,5.1,1.3,1.1,1,0);
>  n <- c(2,2,1,1,1,1,1);
>
> for(i=0;i<7;i++)
>  total = l[i]*n[i]
> total = total / sum(n)     <- this is the weight average
>
>
>
>
>
>
> ______________________________________________
> 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.
>