Adding random values to python list elements

Question

I have a list :

a = [1,2,3,4,5,6,7,8,9,10]

I want to add a different random number to each element in the list using np.random.randn() I start by creating another list containing the rando values by using:

noise = []
for i in range(len(a)):
    b = (random_noise * np.random.randn())
    noise.append(b)

And the add the two lists

a + b

My question is, is there a simplified method in which i can add the noise directly to a elements without the need to creating the loop, in seek of saving time in the large problems.

If you want to switch to numpy, which you probably want to do, then you can generate an array of randoms and add that to the original data. In straight Python, it requires a loop. — Tim Roberts
– Tim Roberts, Commented Sep 13, 2022 at 18:16
It is syntactic sugar, but you could use a list comprehension. — nikeros
– nikeros, Commented Sep 13, 2022 at 18:19

fsimonjetz · Accepted Answer · 2022-09-13 18:20:23Z

2

If you turn a into a numpy array, you can do

>>> a = np.array(a)
>>> a2 = a + np.random.randn(a.size)
>>> a2
array([-0.1199694 ,  1.64558727,  3.10977101,  5.66627737,  4.95481395,
        7.63834891,  7.48148948,  8.55867759,  8.02858298,  9.77297563])

answered Sep 13, 2022 at 18:20

fsimonjetz

5,7923 gold badges7 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Soroush · Accepted Answer · 2022-09-13 18:26:10Z

1

Create the noise as np array and add it to a

import numpy as np
a = [1,2,3,4,5,6,7,8,9,10]
noise = np.random.randn(len(a))
print(a+noise)

answered Sep 13, 2022 at 18:26

Soroush

112 bronze badges

Comments

Roy · Accepted Answer · 2022-09-13 18:23:38Z

0

You can do something like this:

a = [x + np.random.randn() for x in range(1, 10)]
print(a)

output:

[0.31328085156307206, 0.8473128208005949, 4.574220370196114, 3.7338991251803195, 4.9131070198281686, 5.4760389038550565, 7.328982658187497, 6.716468468134682, 9.491303138695487]

answered Sep 13, 2022 at 18:23

Roy

4124 silver badges14 bronze badges

Collectives™ on Stack Overflow

Adding random values to python list elements

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related