First method of swapping, using arithmetic expressions, reqires the variable being swapped to be of numeric type, specifically integer: a = 1 b = 2 # Prints original values of a and b, i.e. 1 and 2: print a, b # Now the swap, using some additions and subtractions. a = a + b b = a - b a = a - b# Prints swapped values of a and b, i.e. 2 and 1: print a, b Second method is simpler, and can work for more types of Python objects, using parallel assignment: a, b = b, a