Python_函数_参数

     def   是函数的关键字,Python解释器一旦执行到def,默认不执行

def li():
    n = 8
    n +=1
    print(n)
li() li2
= li li2()

结果:

9
9

 

return():用于函数返回值,用于中断函数操作

 

参数可以是数字,字符串,列表,元组,字典

默认参数:默认参数Python规定放在普通参数后面

def li(a1,a2=11)
    print(a1,a2)
li(
111) li(111,222)

结果:

111 11
111 222

指定参数:指定后按指定参数的顺序执行

def li(a1,a2)
    print(a1,a2)
li(a2
=32,a1=8)

结果:

8 32

动态参数

  默认元组: 

def show(*arg):
    print(arg,type(arg))
show(
33) show(11,33,66,44,66)

结果:

(33,) <class 'tuple'>
(11, 33, 66, 44, 66) <class 'tuple'>

  默认字典:

def show(**arg):
    print(arg, type(arg))
show( n1
=123, n2= 'hello',n3=5,)

结果:

{'n1': 123, 'n2': 'hello', 'n3': 5} <class 'dict'>

  默认先插入元组,再插入字典:

def show(*args, **kwargs):
    print(args, type(args))
    print(kwargs, type(kwargs))

show(11, 22, 44, 55, n1=88, n2='presly')
l = [11, 22, 44, 55,]
d = {'n1': 123, 'n2': 'hello'}
show(l, d)
show(*l,**d)

结果:

(11, 22, 44, 55) <class 'tuple'>
{'n1': 88, 'n2': 'presly'} <class 'dict'>
([11, 22, 44, 55], {'n1': 123, 'n2': 'hello'}) <class 'tuple'>
{} <class 'dict'>
(11, 22, 44, 55) <class 'tuple'>
{'n1': 123, 'n2': 'hello'} <class 'dict'>

  动态参数实现 字符串格式化:

例:

# s1 = '{0} is {1}'                       # *args的传参
# l = ['Presly', 'lovely']
# # result = s1.format('Presly', 'lovely')
# result = s1.format(*l)
# print(result)
s1 = '{name} is {acter}'             # **kwargs的传参
d = {'name': 'Presly', 'acter': 'lovely'}
result = s1.format(**d)
print(result)

结果:

Presly is lovely

 

posted @ 2018-09-05 20:19  yin_zhaozhao  阅读(172)  评论(0编辑  收藏  举报