How can I nest an If statement in a substr function in R

Question

I am trying to pull apart a numeric field into two parts so I can merge with another data set. The number of characters is 6 or 7 characters long. I was able to get the last characters easily enough, but now I need either the first one or two characters of the field, depending on how long it is. This was my stab at it, but I received a number of errors. Is it possible to nest an If statement like this? Or do I need to swap it and run an If statement in a loop with different assignment statements?

df$new_field <- as.numeric(substr(df$GEOID, 1 ,if(nchar(df$GEOID)=6){
  return(1)
}
else{
  return(2)
}))

Answer 1

With can use ifelse instead of if/else as ifelse is vectorized while if/else takes only a single value of length 1 and returns length 1

df$new_field <- with(df, as.numeric(substr(GEOID, 1, 
                             ifelse(nchar(GEOID) == 6, 1, 2))))

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Or another option is to convert the logical vector to numeric

n  <- (nchar(df$GEOID) != 6) + 1
df$new_field <- with(df, as.numeric(substr(GEOID, 1, n)))

---

Using a reproducible example

v1 <- c('1234567', '123456', '1234')
n  <- (nchar(v1) != 6) + 1
n
#[1] 2 1 2
substr(v1, 1, n)
#[1] "12" "1"  "12"

NOTE: In addition to substr, substring can also be used with the same method