Why 'round' function in python works like this

Question

Output of print(round(51.5)) is 52 but output of print(round(52.5)) is also 52. Does anyone knows why this kolaveri D?

Answer 1

If you want usual sense of rounding, write your own function

def myRound(num) :
if num % 1 == 0.5 :
return num + 0.5
else :
return round(num)

Answer 2

Banker's rounding.

When summing up a large number of bank account amount, helps balance the error caused by keeping rounding up at 0.5

https://wiki.c2.com/?BankersRounding

Answer 3

Is there any other round function which doesn't uses bankers rounding?