function round() doesn't work as I expect [duplicate]

Question

I am trying to use round function here. Sometimes it round down from .5 sometimes round up. So what's the problem?

Source file:

print("rounding up 0.5 is",round(.5))
print("rounding up 1.5 is",round(1.5))
print("rounding up 2.5 is",round(2.5))
print("rounding up 3.5 is",round(3.5))

Output:

rounding up 0.5 is 0
rounding up 1.5 is 2
rounding up 2.5 is 2
rounding up 3.5 is 4

Answer 1

From the docs:

if two multiples are equally close, rounding is done toward the even choice

So when you say rounding up, it's not necessarily rounding up. It's just rounding.