How to do it...

Let's see how to binarize data in Python:

1. To binarize data, we will use the  preprocessing.Binarizer() function as follows (we will use the same data as in the previous recipe):

>> data_binarized = preprocessing.Binarizer(threshold=1.4).transform(data)

The preprocessing.Binarizer() function binarizes data according to an imposed threshold. Values greater than the threshold map to 1, while values less than or equal to the threshold map to 0. With the default threshold of 0, only positive values map to 1. In our case, the threshold imposed is 1.4, so values greater than 1.4 are mapped to 1, while values less than 1.4 are mapped to 0.

1. To display the binarized array, we will use the following code:

>> print(data_binarized)

The following output is returned:

[[ 1.  0.  1.  0.]
 [ 0.  1.  0.  1.]
 [ 0.  1.  0.  0.]]

This is a very useful technique that's usually used when we have some prior knowledge of the data.