How to do the product of arrays of an array in Python

Question

In a single line, how can I get the product of the arrays of an array? I need it to be done for multi columns cases

2 columns example:

X = [[1 4]
     [2 3]
     [0 2]
     [1 5]
     [3 1]
     [3 6]]

sol = [4 6 0 5 3 18]

4 columns example:

X = [[1 4 2 3]
     [2 3 1 5]
     [0 2 3 4]
     [1 5 2 2]
     [3 1 1 6]
     [3 6 3 1]]

sol = [24 30 0 20 18 54]

willeM_ Van Onsem · Accepted Answer · 2020-02-23 11:23:11Z

4

This is a row-wise multiplication. You can perform this with:

X.prod(axis=1)

for example:

>>> X
array([[1, 4],
       [2, 3],
       [0, 2],
       [1, 5],
       [3, 1],
       [3, 6]])
>>> a.prod(axis=1)
array([ 4,  6,  0,  5,  3, 18])

answered Feb 23, 2020 at 11:12

willeM_ Van Onsem

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2 Comments

I don't understand the 'Note'

@Joracosu: sorry, I was talking about your second example. It is not a 4d array, it is a 2d array with four columns in your example.

Pygirl · Accepted Answer · 2020-02-23 11:29:35Z

0

You can also use numpy.multiply.reduce

np.multiply.reduce(x, axis=1)

answered Feb 23, 2020 at 11:29

Pygirl

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