Using an IF statement in R

Question

I'm new to R. I want to do something along the lines of:

if Survive="Y" then Survive1=1 in my dataframe named "od" But, I'm having trouble with the code. This is what I currently have

od$Survive <- c(0)
if(od$Survive=="Y"){
  od$Survive1=1
}

I keep getting this warning:

Warning message: In if (od$Survive == "Y") { : the condition has length > 1 and only the first element will be used

Not quite clear what you are trying to do. Maybe just use logical subsetting: `od$Survive1[od$Survive == "Y"] <- 1`, but you should also look into the `ifelse()` *function* rather than the `if ... else` *construct*. — John Coleman, Nov 26 '19 at 01:25

score 2 · Accepted Answer · answered Nov 26 '19 at 01:26

2

The error you are seeing has to do with that an if statement is not vectorized, and so R is telling you that only the first element of the vector will be used. Try using ifelse for a vectorized solution:

od$Survive1 <- ifelse(od$Survive == "Y", 1, 0)

You could also just assign to the boolean expression:

od$Survive1 <- od$Survive == "Y"

answered Nov 26 '19 at 01:26

Tim Biegeleisen

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Surely this is duplicate? – IRTFM Nov 26 '19 at 05:01

Using an IF statement in R

1 Answers1