Manipulating array shapes

Another recurring task is flattening of arrays. Flattening in this context means transforming a multidimensional array into a one-dimensional array. In this example, we will demonstrate a number of ways to manipulate array shapes starting with flattening:

• ravel(): We can accomplish flattening with the ravel() function (see the shapemanipulation.py file in the Chapter02 folder of this book's code bundle), as shown in the following code:

  In: b
  Out:
  array([[[ 0,  1,  2,  3],[ 4,  5,  6,  7],[ 8,  9, 10, 11]],[[12, 13, 14, 15],[16, 17, 18, 19],[20, 21, 22, 23]]])
  In: b.ravel()
  Out:
  array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23])

• flatten(): The appropriately-named function, flatten(), does the same as ravel(), but flatten() always allocates new memory, whereas ravel() might return a view of an array. This means that we can directly manipulate the array as follows:

  In: b.flatten()
  Out:
  array([ 0,  1,  2,  3,  4,  5...