CODEWITHSUNDEEP
arrayspython-2.7numpy
Marc Monot
Marc Monot

Reputation: 23

Python increment part of an array

I would like to increment part of an array in python as fast as possible. I use a simple loop :

>>> test = [0,0,0,0,0]
>>> for i in xrange(1, 3):
    test[i] += 1

>>> test
[0,1,1,0,0]

In my program the test list contains several millions elements. Maybe numpy could be the solution ?

Thanks,

Marc

Upvotes: 2

Views: 2623

Answers (1)

John Zwinck
John Zwinck

Reputation: 249133

NumPy is indeed a solution:

import numpy as np
arr = np.array(test)
arr[1:3] += 1

You can use arr.tolist() if you really need to go back to a list but better would be to use a NumPy array right from the start, wherever you get your data.

Upvotes: 3

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