Numpy array: multiplication array for each row [duplicate]

Question

I have two array a and b such that b's shape is a row of a. I want to multiply b to each row of a so for example,

#a

[[1,2,3]
 [4,5,6]
 [7,8,9]]

#b
[1,3,2]

# a times b
[[1,6,6]
 [4,15,12]
 [7,24,18]]

Is there any way to perform it?

See broadcasting as well, multiplication will yield expecting results only if the dimensions make sense. numpy.org/doc/stable/user/basics.broadcasting.html — Ananda
– Ananda, Commented Nov 16, 2020 at 10:35

pap · Accepted Answer · 2020-11-16 00:30:13Z

2

This is actually the expected output when using numpy. So in your case:

import numpy as np
a = np.array([[1,2,3], [4,5,6], [7,8,9]])
b = np.array([1,3,2])
c = a*b

c will be:

array([[ 1,  6,  6],
       [ 4, 15, 12],
       [ 7, 24, 18]])

answered Nov 16, 2020 at 0:30

pap

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