Efficient one-liner in Julia to calculate "running" sums? -


is there efficient way following in julia in 1 line of code?

foldl((prev, x)-> [prev; prev[end] + x] , 0, block_lengths)

for example, 

block_lengths = [2, 2, 2, 2, 3]

the desired output is

[0, 2, 4, 6, 8, 11]

(i presume way used foldl above inefficient, because i'm concatenating vector , integer @ each iteration.)

iiuc, can use cumsum:

julia> block_lengths = [2, 2, 2, 2, 3];  julia> cumsum(block_lengths) 5-element array{int32,1}:   2   4   6   8  11  julia> [0; cumsum(block_lengths)] 6-element array{int32,1}:   0   2   4   6   8  11

which should o(n).


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