数据结构和算法-从任意长度的可迭代对象中分解元素

###数据结构和算法-从任意长度的可迭代对象中分解元素

python3
从任意长的对象中分解元素：

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

Python 3.7.1 (default, Dec 14 2018, 13:28:58)
[Clang 4.0.1 (tags/RELEASE_401/final)] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> record = ('guo', 27, '13758214335', '13758214337')
>>> name,age,*number = record
>>> number
['13758214335', '13758214337']
>>> name
'guo'
>>> age
27
>>>

>>> *nums, last = [1, 2, 3, 4, 4, 5]
>>> nums
[1, 2, 3, 4, 4]
>>> last
5

>>> line = 'nobody:*:-2:-2:dhjhjjhjj User:/var/emprty:/usr/bin/false'
>>> uname, *fields, homedir, sh = line.split(':')
>>> uname
'nobody'
>>> fields
['*', '-2', '-2', 'dhjhjjhjj User']
>>> homedir
'/var/emprty'
>>> sh
'/usr/bin/false'
>>>

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)

####执行结果
foo 1 2
bar hello
foo 3 4

大神用迭代

items = [1, 2, 3, 4, 5]

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

print (sum(items))


#执行结果
15