[R] data frame cumulative row sum

Don McKenzie dmck at u.washington.edu
Mon Dec 8 21:26:18 CET 2014


my.data$z <- cumsum(my.data$y)

Yes, the function you need is even in your message subject.

> On Dec 8, 2014, at 12:18 AM, Ragia Ibrahim <ragia11 at hotmail.com> wrote:
> 
> Hi,
> Kindly I had a data frame looks like this
> x y  
> 1 3  
> 2 2  
> 3 1  
> 4 3  
> and I want to add column z that sum cumulativly like this
> x y z
> 1 3 3
> 2 2 5
> 3 1 6
> 4 3 9
> 
> how to do this?
> Regards
> Ragia
> 		 	   		  
> 	[[alternative HTML version deleted]]
> 
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Don McKenzie
Research Ecologist
Pacific Wildland Fire Sciences Lab
US Forest Service

Affiliate Faculty
School of Environmental and Forest Sciences
University of Washington
dmck at uw.edu



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