numpy.reshape(a, newshape, order=‘C’)[source]，参数newshape是啥意思？

newshape : int or tuple of ints

The new shape should be compatible with the original shape. If an integer, then the result will be a 1-D array of that length. One shape dimension can be -1. In this case, the value is inferred from the length of the array and remaining dimensions.

z.reshape(-1)

z.reshape(-1, 1)

z.reshape(-1, 2)

newshape等于-1，列数等于2，行数未知，reshape后的shape等于(8, 2)