If Else Statement in R Error Message

Question

this is my first time using a if-else statement in R. I have a column (in a data frame) named 'Performance' that has percentages (some of which are estimates). I have created a new column named 'Estimate' which takes the last character of the 'Performance' column. Now, I want to make a column with the following conditions: If 'Estimate' = '*' then 'Estimate' = 'YES' else 'Estimate' = 'NO'. I just want to keep the new column name 'Estimate'. The statement I have written works, but I am getting an error message that says:

"Warning message: In if (data.set$Estimate == "*") { : the condition has length > 1 and only the first element will be used"

Here is my statement:

data.set$Estimate <- if (data.set$Estimate == '*') {data.set$Estimate = 'YES'} else{data.set$Estimate = 'NO'}

Can someone please explain why I am getting this error message, and/or what I would need to change to not get it? Any help is much appreciated.

Did you search for this error on SO? There are hundreds of answers to this already. — Rich Scriven
– Rich Scriven, Commented Sep 23, 2014 at 16:01

DMT · Accepted Answer · 2014-09-23 16:00:20Z

1

For the warning, it isn't actually working. A single if statement is expecting a single boolean, yet you try to compare data$Estimate (a vector) to "*" (a single element). It therefore does exactly what it says in the warning, takes the first element only of data$Estimate. Your thought process was good, just didn't quite hit the implementation!

ifelse() allows for vectorization (i.e. a vector of booleans), so it does what you thought the if-else should do. No need for sapply in this case, we can just vectorize.

replace vect below with your data$Estimate

vect<-c("*", "X", "*", "*", "10YEAH", "WHAT", "BlurbBlurb")
vect<-ifelse(vect=="*","Yes", "No" )
vect

#[1] "Yes" "No"  "Yes" "Yes" "No"  "No"  "No"

edited Sep 23, 2014 at 16:00

answered Sep 23, 2014 at 14:12

DMT

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anonR · Accepted Answer · 2014-09-23 13:14:07Z

0

In your column Estimate there are more than one entries containing "*". But if statement uses one logical element only like:

any(data.set$Estimate=="*")

And seeing that you want to replace enteries having * with "YES" you can use

my.fun1<-function(x)
         {
            ifelse(x=="*","YES","NO")
         }
data.set$Estimate<-sapply(data.set$Estimate,my.fun1)

answered Sep 23, 2014 at 13:14

anonR

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