Encoding categorical columns III: DictVectorizer
Alright, one final trick before you dive into pipelines. The two step process you just went through - LabelEncoder followed by OneHotEncoder - can be simplified by using a DictVectorizer. 
Using a DictVectorizer on a DataFrame that has been converted to a dictionary allows you to get label encoding as well as one-hot encoding in one go. 
Your task is to work through this strategy in this exercise!
Diese Übung ist Teil des Kurses
Extreme Gradient Boosting with XGBoost
Anleitung zur Übung
- Import 
DictVectorizerfromsklearn.feature_extraction. - Convert 
dfinto a dictionary calleddf_dictusing its.to_dict()method with"records"as the argument. - Instantiate a 
DictVectorizerobject calleddvwith the keyword argumentsparse=False. - Apply the 
DictVectorizerondf_dictby using its.fit_transform()method. - Hit 'Submit Answer' to print the resulting first five rows and the vocabulary.
 
Interaktive Übung
Vervollständige den Beispielcode, um diese Übung erfolgreich abzuschließen.
# Import DictVectorizer
____
# Convert df into a dictionary: df_dict
df_dict = ____
# Create the DictVectorizer object: dv
dv = ____
# Apply dv on df: df_encoded
df_encoded = ____
# Print the resulting first five rows
print(df_encoded[:5,:])
# Print the vocabulary
print(dv.vocabulary_)