[R] rows process in DF

[Phil Spector]

If you don't mind avoiding a loop, here's one way to
solve your problem:

> myDF = data.frame(id=c(100,101),d1=c(.3,.3),d2=c(.4,.4),d3=c(-.2,.5),d4=c(-.3,.6),d5=c(.5,-.2),d6=c(.6,-.4),d7=c(-.9,-.5),d8=c(-.8,-.6))
> doit = function(x)c(x[1],sum_positive=sum(x[-1][x[-1]>0]),sum_negative=sum(x[-1][x[-1]<0]))
> t(apply(myDF,1,doit))
       id sum_positive sum_negative
[1,] 100          1.8         -2.2
[2,] 101          1.8         -1.7

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


On Wed, 14 Jul 2010, jd6688 wrote:

>
> I have the following datasets:
>
> id  d1  d2   d3   d4   d5   d6   d7   d8
> 1 100 0.3 0.4 -0.2 -0.3  0.5  0.6 -0.9 -0.8
> 2 101 0.3 0.4  0.5  0.6 -0.2 -0.4 -0.5 -0.6
>
> what I am trying to accomplish:
>
> loop through the  rows && do the following:
>    if the values from the columns of the current row >0 then
> sum_positive=total
>    if the values from the columns of the current row <0 then
> sum_negtive=total
>
>    then discard the columns and create a new table
>
>
>     id    sum_positive  sum_negtive
>
> 1  100      1.8           -2.2
> 2   101     1.8           -1.7
>
> I tried the following:but didn't make it work, any inputs would be greatly
> appreciated.
>
> for (i in 1:nrow(myDF))  {
> +    myrow <-myDF[i,]
> +   don't know how to move forward?
> + }
>
> -- 
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>
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