In user-defined function topic, we learned about defining a function and calling it. Otherwise, the function call will result into an error. Here is an example.

Since, we have called this function with two arguments, it runs smoothly and we do not get any error. If we call it with different number of arguments, the interpreter will complain.

Below is a call to this function with one and no arguments along with their respective error messages. Up until now functions had fixed number of arguments.

In Python there are other ways to define a function which can take variable number of arguments.

On the other hand, the parameter msg has a default value of "Good morning! So, it is optional during a call.

If a value is provided, it will overwrite the default value. Any number of arguments in a function can have a default value.

But once we have a default argument, all the arguments to its right must also have default values. This means to say, non-default arguments cannot follow default arguments. For example, if we had defined the function header above as:. When we call a function with some values, these values get assigned to the arguments according to their position.

For example, in the above function greet , when we called it as greet "Bruce","How do you do? Python allows functions to be called using keyword arguments.

When we call functions in this way, the order position of the arguments can be changed.

Anonymous function - Wikipedia

Following calls to the above function are all valid and produce the same result. As we can see, we can mix positional arguments with keyword arguments during a function call. But we must keep in mind that keyword arguments must follow positional arguments. Having a positional argument after keyword arguments will result into errors.

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For example the function call as follows:. Sometimes, we do not know in advance the number of arguments that will be passed into a function. Python allows us to handle this kind of situation through function calls with arbitrary number of arguments. Here, we have called the function with multiple arguments.

These arguments get wrapped up into a tuple before being passed into the function.

Default Parameter Values in Python

Inside the function, we use a for loop to retrieve all the arguments back. MENU menu home Tutorial Examples Methods Quiz search. Python Function Arguments In Python, you can define a function that takes variable number of arguments.

You will learn to define such functions using default, keyword and arbitrary arguments in this article. If message is not provided, it defaults to "Good morning! Check out these examples to learn more: Python Program to Find HCF or GCD.

Dynamic default arguments in python functions - Stack Overflow

Python Program to Find LCM. Python Program to Make a Simple Calculator. Want to learn more Python for Data Science? Head over to DataCamp and try their free Python Tutorial.

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