Python3.x *(单星)和(斜线)作为独立参数有什么作用

有一个new function parameter syntax /指示某些函数参数必须按位置指定，不能用作关键字参数.[103]

文档详细说明了positional-only parameters的一些用例/优点

1. 它允许纯Python函数完全模拟

   def pow(x, y, z=None, /):
       "Emulate the built in pow() function"
       r = x ** y
       return r if z is None else r%z
   

2. 另一个用例是当参数

   len(obj='hello')  # The "obj" keyw或d argument impairs readability
   

3. 将参数标记为仅位置参数的另一个好处是

   def quantiles(dist, /, *, n=4, method='exclusive')
       ...
   

其中as *用于强制caller to use named arguments.This is命名参数的用例之一.

因此，根据这种方法，

def func(self, param1, param2, /, param3, *, param4, param5):
     print(param1, param2, param3, param4, param5)

它一定是打电话来的

obj.func(10, 20, 30, param4=50, param5=60)

或

obj.func(10, 20, param3=30, param4=50, param5=60)

比如，

1. param1, param2 must be specified positionally.
2. param3 can be called either with positional 或 keyw或d.
3. param4 and param5 must be called with keyw或d argument.

演示:

>>> class MyClass(object):
...     def func(self, param1, param2, /, param3, *, param4, param5):
...         return param1, param2, param3, param4, param5
...
>>> obj = MyClass()
>>>
>>> assert obj.func(10, 20, 30, param4=40, param5=50), obj.func(
...     10, 20, param3=30, param4=40, param5=50
... )