python3 cookbook解压可迭代对象赋值给多个变量的问题及解决方案

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

record = ('Dave', 'dave@example.com', '773-555-1212', '847-555-1212')
name, email, *phone_numbers = record
==========================================
name='Dave'
email='dave@example.com'
phone_numbers=['773-555-1212', '847-555-1212']

*trailing_qtrs, current_qtr = sales_record
trailing_avg = sum(trailing_qtrs) / len(trailing_qtrs)
return avg_comparison(trailing_avg, current_qtr)
#下面是在 Python 解释器中执行的结果：
*trailing, current = [10, 8, 7, 1, 9, 5, 10, 3]
 trailing=[10, 8, 7, 1, 9, 5, 10]
 current=3

records = [
			('foo', 1, 2),
			('bar', 'hello'),
			('foo', 3, 4),
			]
def do_foo(x, y):
	print('foo', x, y)
def do_bar(s):
	print('bar', s)
for tag, *args in records:
	if tag == 'foo':
		do_foo(*args)
	elif tag == 'bar':
		do_bar(*args)

line = 'nobody:*:-2:-2:Unprivileged User:/var/empty:/usr/bin/false'
uname, *fields, homedir, sh = line.split(':')
======================================================
uname='nobody'
homedir='/var/empty'
sh='/usr/bin/false'

record = ('ACME', 50, 123.45, (12, 18, 2012))
name, *_, (*_, year) = record
==========================================
name='ACME'
year=2012

items = [1, 10, 7, 4, 5, 9]
head, *tail = items
==========================
head=1
tail=[10, 7, 4, 5, 9]

def sum(items):
	 head, *tail = items
	 return head + sum(tail) if tail else head
sum(items)
==================================
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