if clause in data frame
On Mar 29, 2013, at 10:47 AM, arun wrote:
Hi,
final<-data.frame()
for (m1 in 4:10) {
for (n1 in 4:10){
for (x1 in 0: m1) {
for (y1 in 0: n1) {
final<- rbind(final,c(m1,n1,x1,y1))
res}}}}
final1<-within(final,{flag<-ifelse(x1/m1>y1/n1, 1,0)})
That looks likely to be extremely slow. 'rbind.data.frame' is notoriously slow when applied iteratively in loops. Couldn't this just be: dat <- expand.grid(m1 = 4:10, n1 = 4:10, x1 = 0: m1, y1 = 0: n1) final= within(dat, flag=as.numeric( x1/m1>y1/n1) )
David.
> head(final1)
> # m1 n1 x1 y1 flag
> #1 4 4 0 0 0
> #2 4 4 0 1 0
> #3 4 4 0 2 0
> #4 4 4 0 3 0
> #5 4 4 0 4 0
> #6 4 4 1 0 1
>
>
> Also, just by looking at your code, you have "flag" and "flap".
>
> A.K.
>
>
>
> ________________________________
> From: Joanna Zhang <zjoanna2013 at gmail.com>
> To: arun <smartpink111 at yahoo.com>
> Sent: Friday, March 29, 2013 10:56 AM
> Subject: if clause in data frame
>
>
> Why the if clause code not working here?
>
> final<-data.frame()
> for (m1 in 4:10) {
> for (n1 in 4:10){
> for (x1 in 0: m1) {
> for (y1 in 0: n1) {
>
> if (x1/m1>y1/n1) { flag<-1}
> else {flap<-0}
>
> final<-rbind(final, c(m1,n1,flag, x1,y1))
> }}
> }}
> colnames(final)<-c("m1","n1","flag","x1","y1")
> final
>
David Winsemius
Alameda, CA, USA