Question

Using NumPy, a matrix A has n rows and m columns, and I want add a guard ring to matrix A. That guard ring is all zero.

What should I do? Use Reshape? But the element is not enough to make a n+1 m+1 matrix.

Or etc.?

Thanks in advance

I mean an extra ring of cells that always contain 0 surround matrix A.Basically there is a Matrix B has n+2rows m+2columns where the first row and columns and the last row and columns are all zero,and the rest of it are same as matrix A.

Answer 1

Following up on your comment:

>>> import numpy >>> a = numpy.array(range(9)).reshape((3,3)) >>> b = numpy.zeros(tuple(s+2 for s in a.shape), a.dtype) >>> b[tuple(slice(1,-1) for s in a.shape)] = a >>> b array([[0, 0, 0, 0, 0],        [0, 0, 1, 2, 0],        [0, 3, 4, 5, 0],        [0, 6, 7, 8, 0],        [0, 0, 0, 0, 0]])