What is the most efficient way to iterate over all rows in R?

Asked Aug 22 '14 at 11:56

Active Apr 15 '15 at 15:51

Viewed 63 times

for (i in 1:nrow(df2)){

if (df2$FLAG[i]==0) {df2$AGE[i]<-50}}

df2 is a data frame with around 500,000 rows. So this takes a lot of time to run. Is there a way to optimize this in R?

edited Apr 15 '15 at 15:51

asked Aug 22 '14 at 11:56

Ujjwal

3

Try `df2[df2$FLAG == 0, "AGE"] <- 50` – David Arenburg Aug 22 '14 at 11:58
3

As indicated by David's comment, in R it's mostly the most efficient way not to iterate or loop at all but to use vectorized functions instead. – talat Aug 22 '14 at 12:01
1

Thanks guys. Really appreciate. Big learning here. – Ujjwal Aug 22 '14 at 12:10
@DavidArenburg Post it as an answer. – Thomas Aug 22 '14 at 12:13

0 Answers0