参数练习

def story(**kwds):
    return('Once upon a time.there was a %(job)s called %(name)s.'%kwds)

def power(x,y,*others):
    if others:
        print('Received redundant parameters:'，others)
    return pow(x,y)

def interval(start,stop=None,step=1):
    'Imitates range() for step>0'
    if stop is None:
        start, stop = 0,start
    result = []
    i = start
    while i <stop:
        result.append(i)
        i+=step
    return result

>>> print(story(job='king',name='Gumby'))
Once upon a time.there was a king called Gumby.
>>> print(story(name='Liang',job='leader'))
Once upon a time.there was a leader called Liang.

>>> kwds = {'name':'Morse','job':'detective'}

>>> print(story(**kwds))
Once upon a time.there was a detective called Morse.

>>> del kwds['job']
>>> print(story(job='stroke of genius',**kwds))
Once upon a time.there was a stroke of genius called Morse.

>>> power(2,3)
8
>>> power(3,2)
9
>>> power(y=3,x=2)
8
>>> params = (5,)*2
>>> power(*params)
3125
>>> power(3,3,'hello,world')
Received redundant parameters:hello,world
27
>>> interval(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> interval(1,5)
[1, 2, 3, 4]
>>> power(*interval(3,7)) ###power（[3,4,5,6]）

Received redundant parameters: (5, 6)
81