Problems with control statement if...else in R -

i beginner in r , here's code:

for (i in 1:7){ testing<-vector(length=(length(yy)-3)) if(all(yy[i:(i+2)]==0)) testing[i]<-1 else testing[i]<-na } 

yy refers following vector of length 10:

> yy  [1] 1 0 0 0 0 1 0 1 0 1 

testing predict function output, predict 1 if previous 3 elements in yy 0.if not, not predict anything, , na. since yy has total of 10 elements, testing have total of 7 elements (therefore length 7) however, instead of giving me output of 1s , nas, giving this:

> testing [1] false false false false false false    na 

i cannot figure out why, great. thank you.

you should define testing outside loop:

testing<-vector(length=(length(yy)-3)) (i in 1:7){     if(all(yy[i:(i+2)]==0))         testing[i]<-1     else         testing[i]<-na }   testing [1] na  1  1 na na na na 

for task couls use rollapply zoo:

library(zoo) rollapply(yy, 3, function(x) ifelse(all(x == 0), 1, na)) [1] na  1  1 na na na na na