if else inside for loop

I came across this post about an ifelse statement inside a for loop:

How to create new variables using loop and ifelse statement

var1 <- c(0,0,1,2)
var2 <- c(2,2,2,0)
var3 <- c(0,0,0,2)
var4 <- c(1,2,2,2)

df<-as.data.frame(cbind(var1,var2,var3,var4))
df

 var1 var2 var3 var4 
   0    2    0    1   
   0    2    0    2   
   1    2    0    2   
   2    0    2    2   

Based on the post the output would be:

  var1 var2 var3 var4 new
   0    2    0    1   1
   0    2    0    2   0
   1    2    0    2   1
   2    0    2    2   0

Because if in any element in one row there is 1 the corresponding row in the column (new) will be 1 else it will be 0

I wrote something like this:

for (i in 1:nrow(df)){
  if(mean(df[i,] == 1) == 0){
    df$new[i]<- 0}
  else{
    df$new[i]<- 1    
  }}

However, it is giving this output:

var1 var2 var3 var4 new
 0    2    0    1   1
 0    2    0    2   1
 1    2    0    2   1
 2    0    2    2   1

if I modify the code if(mean(df[i,] == 1) == 0) to if(mean(df[i] == 1) == 0) then it works, but in another cases, if I modify the data frame by including 1 at certain position then if(mean(df[i,] == 1) == 0) is correct and not if(mean(df[i] == 1) == 0).

Can anybody explain this behavior? and how can my loop could be modified to be correct all the times? Any explanation highly appreciated!