Python函数的参数常见分类与用法实例详解

def func(x,y):
  print(x)
  print(y)
func(20,30)
#20,30是实参

def foo(x,y,z):
  print(x,y,z)
foo(1,2,3)

def foo(x,y,z):
  print(x,y,z)
foo(5,9,3)
foo(y=8,x=1,z=4)

def foo(x,y,z):
  print(x,y,z)
foo(1,z=3,y=2) #这样写是正确的
foo(1,z=5) #这个没有遵循实参的规则，所以会报错

def foo(x,y,z):
  print(x,y,z)
foo(x=8,y=7,3) #里面的3就是位置实参，放在后面和中间都是不行的，必须要放在关键字实参的前面

def foo(x,y,z):
  print(x,y,z)
foo(3,y=7,z=8)

def register(name,pasd,sex='yuan'):
  print(name,pasd,sex)
register('liuyuan',22,)
register('xiang',22)
register('xxx',80)

def func(y=1,x): #这是错误的，里面的x为位置形参，不能放在后面。
  pass

s=88
def foo(x,y=s):
  print(x,y)
s='555555555555555'
foo(1)
foo(1,22)

def register(name,hobby,l=None):
  if l is None:
    l=[]
  l.append(hobby)
  print(name,l)
register('liuyuan','play')
register('xiang','read')

def foo(x,y,z,*args):
  print(x,y,z)
  print(args)
foo(1,2,3,4,5,6,7,8,)

def foo(x,y,z,**kwargs):
  print(x,y,z)
  print(kwargs)
foo(x=1,y=2,z=3,a=5,b=6,c=7)

def foo(x,y,z,*args):
  print(x,y,z)
  print(args)
foo(1,2,3,*[4,5,6,7,8,9])
foo(1,2,3,*'h,e,l,l,o')

def foo(x,y,z,**kwargs):
  print(x,y,z)
  print(kwargs)

def index(name,age,gender):
  print('welcome %s %s %s' %(name,age,gender))
def wrapper(*args,**kwargs): #args=(1,2,3),kwargs={'x':1,'y':2,'z':3}
  index(*args,**kwargs) # index(*(1,2,3),**{'x':1,'y':2,'z':3}) # index(1,2,3,z=3,y=2,x=2)
wrapper('egon',age=18,gender='male')
wrapper('egon',18,gender='male')
wrapper('egon',18,'male')