Making it a binary classification problem

For the sake of simplicity, we want to focus on a binary classification problem for now, where we only have two classes. The easiest way to do this is to discard all data points belonging to a certain class, such as class label 2, by selecting all the rows that do not belong to class 2:

In [9]: idx = iris.target != 2
...     data = iris.data[idx].astype(np.float32)
...     target = iris.target[idx].astype(np.float32)