Search code examples
rtie

Ties when finding minimum in R

In the following example, how do I ask the R to select more than one index if there is a tie (For example in row 3 the minimum is 2 which occurs for both x and y columns. However, sapply gives the index for x column only) (My apologizes if this looks like a naive question)

df1< -structure(list(x = c(5, 2, 3), y = c(4, 3, 3)), .Names = c("x", 
"y"), row.names = c(NA, -3L), class = "data.frame")

 df1
  x y
1 5 4
2 2 3
3 3 3
sapply(as.list(rownames(df1)),function(x) which.min(df1[x,]))
y x x 
2 1 1
Solution

  • just change which.min(df1[x,]) to which(df1[x,]==min(df1[x,])). You can even shorten your code by using apply instead of sapply

    > apply(df1, 1, function(x) which(x==min(x)))
[[1]]
y 
2 

[[2]]
x 
1 

[[3]]
x y 
1 2