如何将numpy 2D数组与numpy 1D数组相乘？

Question

两个数组:

a = numpy.array([[2,3,2],[5,6,1]])
b = numpy.array([3,5])
c = a * b

我想要的是:

c = [[6,9,6],
     [25,30,5]]

但是,我收到了这个错误:

ValueError: operands could not be broadcast together with shapes (2,3) (2)

如何将 nD数组乘以 1D数组,在哪里len(1D-array) == len(nD array)？

Answer 1

您需要将数组b转换为(2,1)形状数组,使用None或numpy.newaxis在索引元组中:

import numpy
a = numpy.array([[2,3,2],[5,6,1]])
b = numpy.array([3,5])
c = a * b[:, None]

这是文件.