I created a list like this:
n = [0,0,0,0,0]
now I want to add [100] at index [1,2,3]. so list will become like this -
n = [0,100,100,100,0]
another example: adding[200] at index [3,4], list will become-
n = [0,100,100,300,200]
We can do this by using loops, but using loops it will take O(n) time. I want to know can we add a value at multiple index of a list without using loops?
You can use can numpy (known for his performant code) arrays, the synta is easy
import numpy as np
n = np.zeros(5) # make array of float, use 'np.zeros(5).astype(int)' for int
n[1:4] = 100
n[3:5] += 200
If you print the between each step
[ 0 0 0 0 0]
[ 0 100 100 100 0]
[ 0 100 100 300 200]
Given a list and a list of pairs of indexes and values you want to add on those indexes, you can achieve this the following way
lst = [0] * 10
values = [(3, 100), (5, 200), (7, 300)]
for index, value in values:
lst[index] = value
print(lst) # [0, 0, 0, 100, 0, 200, 0, 300, 0, 0]
In general, you have to iterate over the indexes you want to use, so it cannot be better than this - O(m), where m is the number of indexes.
