categorical_encoding

  • Available in: GBM, DRF, Deep Learning, K-Means
  • Hyperparameter:

Description

This option specifies the encoding scheme to use for handling categorical features. Available schemes include the following:

GBM/DRF

  • auto or AUTO: Allow the algorithm to decide (default)
  • enum or Enum: 1 column per categorical feature
  • one_hot_explicit or OneHotExplicit : N+1 new columns for categorical features with N levels
  • binary or Binary: No more than 32 columns per categorical feature
  • eigen or Eigen: k columns per categorical feature, keeping projections of one-hot-encoded matrix onto k-dim eigen space only

Deep Learning/K-Means

  • auto or AUTO: Allow the algorithm to decide
  • one_hot_internal or OneHotInternal: On the fly N+1 new cols for categorical features with N levels (default)
  • binary or Binary: No more than 32 columns per categorical feature
  • eigen or Eigen: k columns per categorical feature, keeping projections of one-hot-encoded matrix onto k-dim eigen space only

Example

  • r
  • python
library(h2o)
h2o.init()
# import the airlines dataset:
# This dataset is used to classify whether a flight will be delayed 'YES' or not "NO"
# original data can be found at http://www.transtats.bts.gov/
airlines <-  h2o.importFile("http://s3.amazonaws.com/h2o-public-test-data/smalldata/airlines/allyears2k_headers.zip")

# convert columns to factors
airlines["Year"] <- as.factor(airlines["Year"])
airlines["Month"] <- as.factor(airlines["Month"])
airlines["DayOfWeek"] <- as.factor(airlines["DayOfWeek"])
airlines["Cancelled"] <- as.factor(airlines["Cancelled"])
airlines['FlightNum'] <- as.factor(airlines['FlightNum'])

# set the predictor names and the response column name
predictors <- c("Origin", "Dest", "Year", "UniqueCarrier", "DayOfWeek", "Month", "Distance", "FlightNum")
response <- "IsDepDelayed"

# split into train and validation
airlines.splits <- h2o.splitFrame(data =  airlines, ratios = .8, seed = 1234)
train <- airlines.splits[[1]]
valid <- airlines.splits[[2]]

# try using the `categorical_encoding` parameter:
encoding = "OneHotExplicit"

# train your model
airlines_gbm <- h2o.gbm(x = predictors, y = response, training_frame = train, validation_frame = valid,
                        categorical_encoding = encoding, seed = 1234)

# print the auc for the validation set
print(h2o.auc(airlines_gbm, valid=TRUE))