add column values based on other columns in data frame using for and if

Question

I have a dataframe like this:

     id        adit     diag1   diag2       
      2       3         4230    2234        
      3       5         3345    4456        
      4       6         4567    4467

I would like to add other 2 columns, dse1 and dse2 using the pseudo-code below:

if diag1 contains 4230 then dse1 = 1 else dse1 = 0

if diag2 contains 4567 then dse2 =1  else dse2 = 0

I used this:

for (i in 1 : nrow(dse)){
  for (j in 3: ncol(dse)){
     if dse[i,j] %in% ("4320"){dse$dse1 = 1}
        else{dse$dse1 = 0}
    if dse[i,j] %in% ("4567"){dse$dse2 = 1}
        else{dse$dse2 = 0} 
  }
}

But these do not work.

Answer 1

No need to use a loop, just use ifelse, for example

dse = within(dse, {
    dse1 = ifelse(diag1 == 4230, 1, 0)
    dse2 = ifelse(diag2 == 4567, 1, 0)
 })

Answer 2

Don't use the if/else. Go vectorized as in:

dat$dse1 <- as.numeric(dat$diag1 == 4230)
dat$dse2 <- as.numeric(dat$diag2 == 4567)