R help - Apr 2010 - Summing a series made up of part of a vector

Dear colleagues,
I have a data frame that looks so:
*x1 .... x4
1   4.2
2   3.6
3   2.7
.
.
308 n.a.

x4 is a vector of percentages, sorted in descending value. I would  
like to create a new variable that represents the sum of the series of  
values of x4 to that row.  So I would like x5 to look like this.

x5
1 4.2
2 7.8 (4.2 +3.6)
3 10.5 (4.2+3.6+2.7)

308 =na

So the last number in the vector x5 should be 100, as these are all  
percentages.

Any suggestions? Yours truly,
simon Kiss
*********************************
Simon J. Kiss, PhD
SSHRC and DAAD Post-Doctoral Fellow
John F. Kennedy Institute of North America Studies
Free University of Berlin
Lansstra?e 7-9
14195 Berlin, Germany
Cell: +49 (0)1525-300-2812,
Web: http://www.jfki.fu-berlin.de/index.html

Hi

?cumsum

Petr

r-help-bounces at r-project.org napsal dne 07.04.2010 14:26:12:
> Dear colleagues,
> I have a data frame that looks so:
> *x1 .... x4
> 1   4.2
> 2   3.6
> 3   2.7
> .
> .
> 308 n.a.
> 
> x4 is a vector of percentages, sorted in descending value. I would 
> like to create a new variable that represents the sum of the series of 
> values of x4 to that row.  So I would like x5 to look like this.
> 
> x5
> 1 4.2
> 2 7.8 (4.2 +3.6)
> 3 10.5 (4.2+3.6+2.7)
> 
> 308 =na
> 
> So the last number in the vector x5 should be 100, as these are all 
> percentages.
> 
> Any suggestions? Yours truly,
> simon Kiss
> *********************************
> Simon J. Kiss, PhD
> SSHRC and DAAD Post-Doctoral Fellow
> John F. Kennedy Institute of North America Studies
> Free University of Berlin
> Lansstra?e 7-9
> 14195 Berlin, Germany
> Cell: +49 (0)1525-300-2812,
> Web: http://www.jfki.fu-berlin.de/index.html
> 
> ______________________________________________
> 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.

On Apr 7, 2010, at 8:26 AM, Simon Kiss wrote:
> Dear colleagues,
> I have a data frame that looks so:
> *x1 .... x4
> 1   4.2
> 2   3.6
> 3   2.7
> .
> .
> 308 n.a.
>
> x4 is a vector of percentages, sorted in descending value. I would  
> like to create a new variable that represents the sum of the series  
> of values of x4 to that row.  So I would like x5 to look like this.
>
?cumsum
> x5
> 1 4.2
> 2 7.8 (4.2 +3.6)
> 3 10.5 (4.2+3.6+2.7)
>
> 308 =na
Now that might pose problems. How do you define sum( c(1, NA) ) ?
>
> So the last number in the vector x5 should be 100, as these are all  
> percentages.
>
> Any suggestions? Yours truly,
> simon Kiss
> *********************************
> Simon J. Kiss, PhD
> SSHRC and DAAD Post-Doctoral Fellow
> John F. Kennedy Institute of North America Studies
> Free University of Berlin
> Lansstra?e 7-9
> 14195 Berlin, Germany
> Cell: +49 (0)1525-300-2812,
> Web: http://www.jfki.fu-berlin.de/index.html
>
> ______________________________________________
> 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