Is there a fast way to create a submatrix?

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sage: version()
'Sage Version 4.0.alpha0, Release Date: 2009-05-15'
sage: G = graphs.GridGraph([100,100])
sage: L = G.laplacian_matrix()
sage: L
10000 x 10000 sparse matrix over Integer Ring
sage: time M = L[1:9999,1:9999]
CPU times: user 24.93 s, sys: 0.04 s, total: 24.97 s
Wall time: 25.27 s


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I am just interested in deleting a single row and column of the matrix
(not necessarily the first).

Thanks,
Dave
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