[R] Writing Complex Formulas
Berend Hasselman
bhh at xs4all.nl
Fri Jul 15 20:31:07 CEST 2011
warmstron1 wrote:
>
>> for(j in 1:J)
> + {
> + Z <- dummy**B[j]
> + U <- (-dummy+1)**B[j]
> + }
>> Z
>
I replaced ** with ^ and got the same results as you.
But why are you doing a for loop here?
At each iteration you are overwriting the previous results of Z and U and
retaining only the values obtained for j=J.
You could just as well do
Z <- dummy^B[J] # J and not j
U <- (-dummy+1)^B[J] # same
I got the same results as you.
>> for(i in 1:4)
> + {
> + for(j in 1:3){
> + U[i,j]<-ifelse( U[i,j]>30,30,U[i,j])
> + }
> + U <- exp(U)
>
The second closing } seems to be missing.
Why are you using ifelse elementwisely?
It is a vectorized function.
This is equivalent to what you are doing
U <- ifelse(U>30,30,U)
and still gives the same results.
Berend
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