How to multiply array with a number in python

S = [22, 33, 45.6, 21.6, 51.8]
P = 2.45

Here S is an array

How will I multiply this and get the value?

SP = [53.9, 80.85, 111.72, 52.92, 126.91]

Georgy

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asked Nov 19, 2011 at 15:19

1

In NumPy it is quite simple

import numpy as np
P=2.45
S=[22, 33, 45.6, 21.6, 51.8]
SP = P*np.array[S]

I recommend taking a look at the NumPy tutorial for an explanation of the full capabilities of NumPy's arrays:

//scipy.github.io/old-wiki/pages/Tentative_NumPy_Tutorial

Georgy

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answered Nov 19, 2011 at 15:25

JoshAdelJoshAdel

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0

You can use built-in map function:

result = map[lambda x: x * P, S]

or list comprehensions that is a bit more pythonic:

result = [x * P for x in S]

answered Nov 19, 2011 at 15:22

KL-7KL-7

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2

If you use numpy.multiply

S = [22, 33, 45.6, 21.6, 51.8]
P = 2.45
multiply[S, P]

It gives you as a result

array[[53.9 , 80.85, 111.72, 52.92, 126.91]]

nbro

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answered May 14, 2013 at 17:50

DKKDKK

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Here is a functional approach using map, itertools.repeat and operator.mul:

import operator
from itertools import repeat


def scalar_multiplication[vector, scalar]:
    yield from map[operator.mul, vector, repeat[scalar]]

Example of usage:

>>> v = [1, 2, 3, 4]
>>> c = 3
>>> list[scalar_multiplication[v, c]]
[3, 6, 9, 12]

answered Apr 3, 2019 at 9:34

GeorgyGeorgy

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Posted on: March 12, 2021 by Deven

In this article, you will learn how to multiply array by scalar in python.

Let’s say you have 2 arrays that need to be multiplied by scalar n .

array1 = np.array[[1, 2, 3]]
array2 = np.array[[[1, 2], [3, 4]]]
n = 5

Numpy multiply array by scalar

In order to multiply array by scalar in python, you can use np.multiply[] method.

import numpy as np
array1 = np.array[[1, 2, 3]]
array2 = np.array[[[1, 2], [3, 4]]]
n = 5
np.multiply[array1,n]
np.multiply[array2,n]

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