Variable parameters of functions in Python

Preface

When defining a function in Python, you can use required parameters, default parameters, variable parameters and keyword parameters. These four parameters can be used together. , or only use some of them, but please note that the order of parameter definition must be: required parameters, default parameters, variable parameters and keyword parameters.

Variable parameters (*)

Variable parameters, as the name suggests, are variable parameters, such as lists, dictionaries, etc. If we need a function to handle a variable number of parameters, we can use variable parameters.

When we look at a lot of Python source code, we often see a function definition such as a certain function (*parameter 1, **parameter 2). The *parameter and **parameter are variable parameters. It's a bit confusing for people. In fact, as long as the definition of function variable parameters is clear, it is not difficult to understand.

When we don’t know how many parameters we need to define a function, variable parameters can come into play.

In Python, parameters with * are used to accept a variable number of parameters.

If a function is defined as follows:

def functionTest(*args): 
 .... 
 .... 
 ....

When called, we can call it like this:

functionTest(1) 
或者 
functionTest(1,2) 
或者 
functionTest(1,2,3)

Multiple parameters can be passed in later.

Look at the example code and observe how * is applied:

def get_sum(*numbers): 
 sum = 0 
 for n in numbers: 
  sum += n 
 return sum 
  
#在这里写下你的代码来调用get_sum来求5个数字的和，并输出这个结果 
print (get_sum(1,2,3,4,5))

What will the result be? You can do it yourself and take a look. This is all about the variable parameters of functions in Python. I hope this article can be helpful to everyone in learning or using python. If you have any questions, you can leave a message to communicate.

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