python 交换两个变量的值

# 交换两个变量的值
a = 100
b = 200

# 方法1
# a = a + b
# b = a - b
# a = a - b

# print( "a是%d" % a)
# print("b是%d" % b)

# 方法2
a, b = b, a

print( "a是%d" % a)
print("b是%d" % b)