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  3. Case Study: School Budgeting with Machine Learning in Python

Exercise

Encode the labels as categorical variables

Remember, your ultimate goal is to predict the probability that a certain label is attached to a budget line item. You just saw that many columns in your data are the inefficient object type. Does this include the labels you're trying to predict? Let's find out!

There are 9 columns of labels in the dataset. Each of these columns is a category that has many possible values it can take. The 9 labels have been loaded into a list called LABELS. In the Shell, check out the type for these labels using df[LABELS].dtypes.

You will notice that every label is encoded as an object datatype. Because category datatypes are much more efficient your task is to convert the labels to category types using the .astype() method.

Note: .astype() only works on a pandas Series. Since you are working with a pandas DataFrame, you'll need to use the .apply() method and provide a lambda function called categorize_label that applies .astype() to each column, x.

Instructions

100 XP
  • Define the lambda function categorize_label to convert column x into x.astype('category').
  • Use the LABELS list provided to convert the subset of data df[LABELS] to categorical types using the .apply() method and categorize_label. Don't forget axis=0.
  • Print the converted .dtypes attribute of df[LABELS].