from mpmath import matrix
# Create a 3x3 matrix
A = matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
# Access the last element of the first row
print(A[0, -1])
I expect negative index -n to indicate last n element, like in Python list or numpy array. But I got 0.
After some digging, I found the related code:
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# single element extraction |
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if key[0] >= self._rows or key[1] >= self._cols: |
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raise IndexError('matrix index out of range') |
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if key in self._data: |
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return self._data[key] |
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else: |
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return self.ctx.zero |
The same goes for index of columns, such as A[-1,:] returns [0.0 0.0 0.0].
Are negative indices for other purposes? Can Python-like negative indices be supported?
I expect negative index
-nto indicate last n element, like in Python list or numpy array. But I got0.After some digging, I found the related code:
mpmath/mpmath/matrices/matrices.py
Lines 499 to 505 in cf98bcf
The same goes for index of columns, such as
A[-1,:]returns[0.0 0.0 0.0].Are negative indices for other purposes? Can Python-like negative indices be supported?