Using the array interface

The array interface is a yet another mechanism to communicate with other Python applications. This protocol, as its name suggests, is only applicable to array-like objects. A demonstration is in order. Let's use PIL again, but without saving files.

Getting ready

We will be reusing part of the code from the previous recipe, so the prerequisites are similar. We will skip the first step of the previous step here, and assume it is already known.

How to do it...

The following steps will let us explore the array interface:

1. The PIL image array interface attribute.

   The PIL image object has a __array_interface__ attribute. Let's inspect its contents. The value of this attribute is a dictionary:

   array_interface = img.__array_interface__
   print "Keys", array_interface.keys() 
   print "Shape", array_interface['shape'] 
   print "Typestr", array_interface['typestr']

   This code prints the following information:

   Keys ['shape', 'data', 'typestr']
   Shape (512, 512, 4)
   Typestr |u1
   

2. The NumPy array...