[R] data frame cumulative row sum

[Rolf Turner]

On 08/12/14 21:18, Ragia Ibrahim 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?

(1) Learn to use R.  This is very basic; read some introductory 
material.  Start with "An Introduction to R" from the R web site.

This is analogous to the assertion that you shouldn't be driving a car 
if you haven't a clue how to drive.

(2) Try:

X$z <- cumsum(X$y)

where X is the data frame in question.

cheers,

Rolf Turner

-- 
Rolf Turner
Technical Editor ANZJS