What does -1 mean in numpy reshape?
A numpy matrix can be reshaped into a vector using reshape function with parameter -1. But I don't know what -1 means here.
For example:
a = numpy.matrix([[1, 2, 3, 4], [5, 6, 7, 8]])
b = numpy.reshape(a, -1)
The result of b is: matrix([[1, 2, 3, 4, 5, 6, 7, 8]])
Does anyone know what -1 means here?
And it seems python assign -1 several meanings, such as: array[-1] means the last element. Can you give an explanation?