28. Dict-to-array conversion

A python dictionary can’t be read directly into an sklearn classification or regression algorithm; instead, it needs a numpy array or a list of lists (each element of the list (itself a list) is a data point, and the elements of the smaller list are the features of that point).

We’ve written some helper functions ( featureFormat() and targetFeatureSplit() in tools/feature_format.py ) that can take a list of feature names and the data dictionary, and return a numpy array.

In the case when a feature does not have a value for a particular person, this function will also replace the feature value with 0 (zero).