Connected components from an adjacency matrix using Numpy or Scipy

While you could indeed use DFS to find the connected components, SciPy makes it even easier with scipy.sparse.csgraph.connected_components. With your example:

In [3]: connected_components(test)                                                              
Out[3]: (2, array([0, 0, 0, 1, 1, 1, 1], dtype=int32))