If I have an array [a,b,c], how can I convert it to [a b c, b c, c] in the most efficient way?

(a, b, c) are floats.

Thanks!

CodePudding user response：

You can use np.cumsum:

import numpy as np

a = np.array([1, 2, 3])
print(np.cumsum(a[::-1])[::-1])
# Outputs [6 5 3]

CodePudding user response：

Use numpy.cumsum() on the reversed array, then reverse it again. cumsum([a,b,c]) returns [a,a b,a b c].

import numpy as np

x = [3,7,14]

y = np.cumsum(x[::-1])[::-1]

print(y)