* and * * parameters of Python

* Single star parameter

The single star parameter in the function represents that... Is accepted here   Any number of Non key parameters , These parameters will be saved as an array , for example ：

def foo(a, *b):
print(b)
foo(1,2,3,4,5)
Output (2, 3, 4, 5)

** Multi star parameter

The multi star parameter in the function represents the acceptance here   Any number of keyword parameters , These parameters are stored as dictionaries , for example ：

def foo(a, **b):
print(b)
foo(a=1, b=2, c=3, d=4, e=5)
Output {'c': 3, 'b': 2, 'e': 5, 'd': 4}

  effect ： Change parameters into variable parameters （ In other words, you can not pass , It can also be passed without parameters ）