[R] loop in function

[Stephen Tucker]

Actually I am not sure what you want exactly, but is it

df1 <-data.frame(b=c(1,2,3,4,5,5,6,7,8,9,10))
df2 <-data.frame(x=c(1,2,3,4,5), y=c(2,5,4,6,5), z=c(10, 8, 7, 9, 3))
df1 <- cbind(df1,
             "colnames<-"(sapply(with(df2,(x+y)/z),
                                 function(a,b) a/b,b=df1$b),
                          paste("goal",seq(nrow(df2)),sep="")))

> round(df1,2)
    b goal1 goal2 goal3 goal4 goal5
1   1  0.30  0.88  1.00  1.11  3.33
2   2  0.15  0.44  0.50  0.56  1.67
3   3  0.10  0.29  0.33  0.37  1.11
4   4  0.07  0.22  0.25  0.28  0.83
5   5  0.06  0.17  0.20  0.22  0.67
6   5  0.06  0.17  0.20  0.22  0.67
7   6  0.05  0.15  0.17  0.19  0.56
8   7  0.04  0.12  0.14  0.16  0.48
9   8  0.04  0.11  0.12  0.14  0.42
10  9  0.03  0.10  0.11  0.12  0.37
11 10  0.03  0.09  0.10  0.11  0.33

each column "goal" corresponds to row of df1. Alternatively, the sapply()
function can be rewritten with apply():

apply(df2,1,
      function(a,b) (a["x"]+a["y"])/(a["z"]*b),
      b=df1$b)

Hope this answered your question...

--- sumfleth at geographie.uni-kiel.de wrote:

> Dear Mailing-List,
> I think this is a newbie question. However, i would like to integrate a
> loop in the function below. So that the script calculates for each
> variable within the dataframe df1 the connecting data in df2. Actually it
> takes only the first row. I hope that's clear. My goal is to apply the
> function for each data in df1. Many thanks in advance. An example is as
> follows:
> 
> df1 <-data.frame(b=c(1,2,3,4,5,5,6,7,8,9,10))
> df2 <-data.frame(x=c(1,2,3,4,5), y=c(2,5,4,6,5), z=c(10, 8, 7, 9, 3))
> attach(df2)
> myfun = function(yxz) (x + y)/(z * df1$b)
> df1$goal <- apply(df2, 1, myfun)
> df1$goal
> 
> regards,
> 
> kay
> 
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