Label Encoder functionality in R?

Question

In python, scikit has a great function called LabelEncoder that maps categorical levels (strings) to integer representation.

Is there anything in R to do this?

Answer 1

Try CatEncoders package. It replicates the Python sklearn.preprocessing functionality.

# variable to encode values
colors = c("red", "red", "blue", "green")
lab_enc = LabelEncoder.fit(colors)

# new values are transformed to NA
values = transform(lab_enc, c('red', 'red', 'yellow'))
values

# [1]  3  3 NA


# doing the inverse: given the encoded numbers return the labels
inverse.transform(lab_enc, values)
# [1] "red" "red" NA   

I would add the functionality of reporting the non-matching labels with a warning.

PS: It also has the OneHotEncoder function.