a = 4
b = 5
#第 1 种
c = 0
c = a
a = b
b = c
#第 2 种
a = a+b
b = a-b
a = a-b
#第 3 种
a,b = b,a
print("a=%d,b=%d"%(a,b))
来源: http://www.bubuko.com/infodetail-2446846.html