how can I randomly select an element from a 2d array and then add to it?
amount_to_add = 13
my_array = [[0,0],[0,0],[0,0]]
I want to randomly add 13 to one of the elements so it'd look like
my_array = [[0,0],[0,13],[0,0],[0,0]]
2 Answers
import random
my_array[random.randrange(len(my_array))].append(amount_to_add)
Just that simple.
Demo:
>>> my_array = [[0],[0],[0],[0]]
>>> my_array[random.randrange(len(my_array))].append(amount_to_add)
>>> my_array[random.randrange(len(my_array))].append(amount_to_add)
>>> my_array
[[0], [0], [0, 10], [0, 10]]
Edit: Turns out i misunderstood the question. Here is how to add:
>>> my_array = [[0,0],[0,0],[0,0],[0,0]]
>>> random.choice(my_array)[random.randrange(len(choice))] += amount_to_add
>>> my_array
[[0, 10], [0, 0], [0, 0], [0, 0]]
>>> random.choice(my_array)[random.randrange(len(choice))] += amount_to_add
>>> my_array
[[0, 10], [0, 0], [0, 0], [0, 10]]
1 Comment
roippi
This adds a new element to a random sublist. Not what he asked for.
This works:
>>> from random import choice, randint
>>> amount_to_add = 13
>>> my_array = [[0,0],[0,0],[0,0]]
>>> element = choice(my_array)
>>> element[randint(0, len(element)-1)] += amount_to_add
>>> my_array
[[13, 0], [0, 0], [0, 0]]
>>> my_array = [[0,0],[0,0],[0,0]]
>>> element = choice(my_array)
>>> [randint(0, len(element)-1)] += amount_to_add
>>> my_array
[[0, 0], [0, 0], [0, 13]]
>>>
It randomly chooses an element in my_array, randomly chooses an index on that element, and then adds amount_to_add to the item at that index.
my_arraysupposed to have an additional list in it? Or should it be the same length as the originalmy_array?