从任意长的可迭代对象中分解元素（*式方法）

1 def drop_first_last(grades):
2     first,*middle,last = grades
3     return avg(middle)

 1 records = [(‘foo‘,1,2),(‘bar‘,‘hello‘),(‘foo‘,3,4)]
 2 def do_foo(x,y):
 3     print(‘foo‘,x,y)
 4     
 5 def do_bar(s):
 6     print(‘bar‘,s)
 7     
 8 for tag,*args in records:
 9     if tag == ‘foo‘:
10         do_foo(*args)
11     elif tag == ‘bar‘:
12         do_bar(*args)
13         

1 foo 1 2
2 bar hello
3 foo 3 4