a = "hello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello worldhello world"
b = "hello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dearhello dear"
print id(a),id(b)
print a
print b
a,b = b,a
print a
print b
print id(a),id(b)
整个操作其实是先进行右边,生成一个元组(b,a) 然后再将该元组 解包,分别赋值给左边的 a,b,实现达到交换值的目的