What is the parameter matching model in Python function
Today, I will talk to you about what the parameter matching model in the Python function is. Many people may not know much about it. In order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.
Parameter matching model of Python function
Any parameter *
When our function receives any number of parameters, or cannot determine the number of parameters, we can use * to define any number of parameters. When this function is called, all its mismatched positional parameters are assigned to tuples. We can use loops or indexes in the function.
Def f (* args): # Direct print tuple parameter print (args) print ('-'* 20) # print tuple parameter [print (I) for i in args]... # pass one parameter f (1) print ('='* 20) # pass five parameters f (1, 2, 3, 4, 5)
Example result:
(1,)-1 = (1,2,3,4,5)-12345
# arbitrary parameters * *
And * * is used to collect keyword parameters and pass them to a new dictionary, that is, in the function, we can handle these parameters in the same way as dictionaries.
Def f (* * args): # directly print dictionary parameters print (args) for key, value in args.items (): print ('{}: {} '.format (key, value)) f (axi1) print (' ='* 20) f (axi1, bao2, cym3)
Example result:
{'averse: 1} a: 1 = {' averse: 1, 'baked: 2,' cached: 3} a: 1b: 2c: 3
Arbitrary parameter mixing
We can mix general parameters, * parameters, and * parameters to achieve more complex invocation methods.
Def f (a, * targs, * * dargs): print (a, targs, dargs) f
Example result:
1 (2,3) {"x": 1, "y": 2}
We can see that this kind of call is not so intuitive, and even some "confuse the public", so how can it be more intuitive in the function call when calling a complex arbitrary parameter?
Unpacking parameters
When we call a function, we can directly use * and * to pass parameters, and then let the function unpack automatically, which is similar to the previous sequence unpacking, which makes it more intuitive to use the call.
Def f (a, b, c, d): print (a, b, c, d) f (1, * (2, 3), * * {'dudes: 4})
Example result:
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