What is the difference between Numpy's array() and asarray() functions?

Question

What is the difference between Numpy\'s array() and asarray() functions? When should you use one rather than the other? They seem to generate identical output for all the in

Answer 1

The difference can be demonstrated by this example:

1. generate a matrix

   >>> A = numpy.matrix(numpy.ones((3,3)))
   >>> A
   matrix([[ 1.,  1.,  1.],
           [ 1.,  1.,  1.],
           [ 1.,  1.,  1.]])
   

2. use numpy.array to modify A. Doesn't work because you are modifying a copy

   >>> numpy.array(A)[2]=2
   >>> A
   matrix([[ 1.,  1.,  1.],
           [ 1.,  1.,  1.],
           [ 1.,  1.,  1.]])
   

3. use numpy.asarray to modify A. It worked because you are modifying A itself

   >>> numpy.asarray(A)[2]=2
   >>> A
   matrix([[ 1.,  1.,  1.],
           [ 1.,  1.,  1.],
           [ 2.,  2.,  2.]])
   

Hope this helps!