Reordering levels of a factor variable

Question

I am working with the iris dataset and this is the normal ordering of levels i get w.r.t the Species column:

levels(iris$Species)
[1] "setosa"     "versicolor" "virginica"

I would want to change the ordering of levels to -> "virginica" "versicolor" "setosa", i.e, i want to reverse the order of levels

Answer 1

The factor() function provides the 'levels' attribute for this purpose:

iris$Species <- factor(iris$Species, levels =c("virginica","versicolor","setosa") ) 

All you have to do is, use the levels attribute and reorder the factors.