Let’s say the rows of A are r1, r2, r3. Then the following have the same meaning:
A |> eachrow |> sum
sum(eachrow(A))
sum([r1, r2, r3]) # Sum of a list of 3 elements (each element being a vector)
r1 + r2 + r3
Your list comprehension does something else… These are equivalent:
[sum(r) for r in eachrow(A)] # Calculate sum(r) for each row r
[sum(r1), sum(r2), sum(r2)]
Here instead of calculating the sum of three arrays we calculate three sums!