see Putting a guard on when loading a map
from ABC170_F Make a one-dimensional array of strings with sentry as long as they are newlines. python
C = np.zeros((H + 2, W + 2), np.bool_)
C[1:-1, 1:-1] = np.frombuffer(read(), 'S1').reshape(H, -1)[:, :W] == b'.'
C = C.ravel()
H += 2
W += 2
ValueError: could not broadcast input array from shape (3,0) into shape (3,5)- already read all data from stdin
Explanation of each step python
>>> np.frombuffer(b"...\n.@.\n...\n", "S1")
array([b'.', b'.', b'.', b'\n', b'.', b'@', b'.', b'\n', b'.', b'.', b'.',
b'\n'], dtype='|S1')
>>> _.reshape(3, -1)
array([[b'.', b'.', b'.', b'\n'],
[b'.', b'@', b'.', b'\n'],
[b'.', b'.', b'.', b'\n']], dtype='|S1')
>>> _[:,:3]
array([[b'.', b'.', b'.'],
[b'.', b'@', b'.'],
[b'.', b'.', b'.']], dtype='|S1')
>>> _ == b"."
array([[ True, True, True],
[ True, False, True],
[ True, True, True]])
>>> C = np.zeros((3 + 2, 3 + 2), np.bool_)
>>> C[1:-1, 1:-1] = _
>>> C
array([[False, False, False, False, False],
[False, True, True, True, False],
[False, True, False, True, False],
[False, True, True, True, False],
[False, False, False, False, False]])
>>> C.ravel()
array([False, False, False, False, False, False, True, True, True,
False, False, True, False, True, False, False, True, True,
True, False, False, False, False, False, False])
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