Python *args and *kwargs

A Comprehensive Tutorial with Code Examples

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‍If you’ve ever seen the Python code that uses *args and **kwargs, you may have found it confusing and wondered what it really means. In this article, we’ll take a deep dive into these terms and look at how they can be used in Python programming. We’ll discuss what *args and **kwargs are and how to use them to pass arguments to a function. We’ll also look at examples of *args and **kwargs in Python and explore the differences between the two. Finally, we’ll provide a Python *args and **kwargs example to illustrate how they can be used together.

What are args and *kwargs in Python?

*args and **kwargs are two special terms used in Python, and they are often seen in function definitions. The *args term is used to pass a non-keyworded, variable-length argument list to a function, and **kwargs allows you to pass keyworded, variable-length argument lists. In other words, *args and **kwargs are special syntaxes that allow you to pass a variable number of arguments to a function.

The *args term is used to pass an arbitrary number of non-keyworded arguments to a function. When you use *args, the arguments are passed as a tuple, which is a collection of objects that can be accessed using an index. The **kwargs term is used to pass an arbitrary number of keyworded arguments to a function. When you use **kwargs, the arguments are passed as a dictionary, which is a collection of key-value pairs that can be accessed using a key.

The *args and **kwargs terms are often used together in Python programming. They are useful when you want to pass a variable number of arguments to a function. However, it’s important to note that the *args and **kwargs terms are not required in Python and can be omitted if you don’t need to pass a variable number of arguments.

Examples of *args and **kwargs in Python

Now that we know what *args and **kwargs are, let’s take a look at some examples of how they can be used in Python. Here’s an example of a simple function that uses *args to accept a variable number of non-keyworded arguments:

def my_function(*args): 
   for arg in args: 
       print(arg)

my_function('hello', 'world', 'foo', 'bar')

In this example, we’ve defined a function called my_function() that takes an arbitrary number of non-keyworded arguments. We’ve then passed four arguments to this function. When this function is called, the four arguments are passed as a tuple to the *args parameter.

Here’s an example of a function that uses **kwargs to accept a variable number of keyworded arguments:

def my_function(**kwargs): 
    for key, value in kwargs.items(): 
        print(key, '=', value)

my_function(fruit='apple', vegetable='carrot')

In this example, we’ve defined a function called my_function() that takes an arbitrary number of keyworded arguments. We’ve then passed two keyworded arguments to this function. When this function is called, the two keyworded arguments are passed as a dictionary to the **kwargs parameter.

How to Use *args and **kwargs in Python

Now that we’ve seen some examples of *args and **kwargs in Python, let’s take a look at how to use them in function definitions. Here’s an example of a function definition that uses *args and **kwargs to accept a variable number of arguments:

def my_function(*args, **kwargs): 
       # Do something pass

In this example, we’ve defined a function called my_function() that takes an arbitrary number of arguments. We’ve then passed *args and **kwargs as parameters to this function. This means that any number of non-keyworded and keyworded arguments can be passed to this function.

It’s important to note that the *args and **kwargs parameters must come after any other parameters in the function definition. This is because the *args and **kwargs parameters are used to capture any extra arguments that are passed to the function.

When to Use *args and **kwargs

Now that we know how to use *args and **kwargs, let’s take a look at when they should be used. The *args and **kwargs terms are useful when you want to pass a variable number of arguments to a function. For example, if you want to create a function that can take any number of arguments, you can use the *args and **kwargs terms to do this.

It’s also important to note that the *args and **kwargs terms are not required in Python. If you don’t need to pass a variable number of arguments to a function, you can omit the *args and **kwargs parameters.

Python *args and **kwargs Example

Now that we’ve discussed when to use *args and **kwargs, let’s take a look at an example of how they can be used together. Here’s an example of a function that uses both *args and **kwargs to accept a variable number of arguments:

def my_function(args, *kwargs):
   for arg in args: 
       print(arg) 
   for key, value in kwargs.items(): 
       print(key, '=', value)

my_function('hello', 'world', fruit='apple', vegetable='carrot')

In this example, we’ve defined a function called my_function() that takes an arbitrary number of arguments. We’ve then passed both *args and **kwargs as parameters to this function. This means that any number of non-keyworded and keyworded arguments can be passed to this function. When this function is called, the two non-keyworded arguments are passed as a tuple to the *args parameter, and the two keyworded arguments are passed as a dictionary to the **kwargs parameter.

Difference between *args and **kwargs

Now that we’ve seen an example of *args and **kwargs in Python, let’s take a look at the differences between the two. The *args term is used to pass a non-keyworded, variable-length argument list to a function, and **kwargs allows you to pass keyworded, variable-length argument lists. This means that *args is used to pass a variable number of non-keyworded arguments to a function, and **kwargs is used to pass a variable number of keyworded arguments to a function.

It’s also important to note that the *args and **kwargs parameters must come after any other parameters in the function definition. This is because the *args and **kwargs parameters are used to capture any extra arguments that are passed to the function.

Using *args and **kwargs to Pass Parameters

Now that we know the differences between *args and **kwargs, let’s take a look at how to use them to pass parameters to a function. Here’s an example of a function definition that uses *args and **kwargs to accept a variable number of parameters:

def my_function(*args, **kwargs):
# Do something pass

In this example, we’ve defined a function called my_function() that takes an arbitrary number of parameters. We’ve then passed *args and **kwargs as parameters to this function. This means that any number of non-keyworded and keyworded parameters can be passed to this function.

*args and **kwargs to Pass Arguments in a Class

Finally, let’s take a look at how to use *args and **kwargs to pass arguments to a class. Here’s an example of a class definition that uses *args and **kwargs to accept a variable number of arguments:

class MyClass(*args, **kwargs):  
   def __init__(self, *args, **kwargs): 
       # Do something pass

In this example, we’ve defined a class called MyClass() that takes an arbitrary number of arguments. We’ve then passed *args and **kwargs as arguments to this class. This means that any number of non-keyworded and keyworded arguments can be passed to this class.

Conclusion

Now that you know how to use *args and **kwargs in Python, why not try it out in your own code? You can start by creating a function that uses *args and **kwargs to accept a variable number of arguments. Once you get the hang of it, you’ll be able to use *args and **kwargs to easily pass arguments to your functions.