Python *args and *kwargs

A Comprehensive Tutorial with Code Examples

 

‍If you’ve ever seen a script that uses Python *args and **kwargs, you may have found it confusing and wondered what it really means. In this article, we’ll explore into these terms and look at how they can be used in Python programming. We’ll discuss what Python *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.

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.

Difference between Python *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

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 Python *args and **kwargs, why not try it out in your own code? You can start by creating a function that uses them 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.

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