Python Difference Between Iterable And Iterator Tutorial – Complete Guide

In today’s technological world, whether you’re creating game mechanics or designing a productivity app, understanding the subtle nuances of Python can make a fundamental difference in your coding efficiency. In this light, our tutorial today aims to untangle the intricacies around two key Python concepts – iterable and iterator. Grasping the difference between these two concepts is crucial to becoming a more proficient Python programmer, starting from simpler tasks thill more complex undertakings.

What Is An Iterable?

At the most basic level, an iterable in Python refers to any object capable of returning its elements one at a time. This could be a variety of built-in types such as lists, dictionaries, and strings, or more complex custom objects created using Python classes.

What Is An Iterator?

On the other hand, an iterator is what Python uses to iterate, or loop over, an iterable. In Python, an iterator is an object that contains a countable number of values and allows you to iterate upon it using a concept known as the Iterator Protocol.

Why Learn The Difference?

Understanding the distinct roles of iterables and iterators not only increases your fluency in Python, it also enhances your capacity to write more readable and efficient code. Plus, as these concepts are fundamental to numerous built-in Python functions and structures, mastering them will unlock a more profound understanding of Python’s capabilities.

Stay tuned as we delve deeper into these concepts, offering you easy-to-follow examples that clearly distinguish the role of an iterable and an iterator. Whether you’re just starting your coding journey or an experienced developer looking to hone your Python skills, this tutorial has something valuable for everyone. Be prepared to gain a solid foundation on iterables and iterators that could take your coding game up a notch!

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Working with Iterables

Let’s look at a simple example of an iterable. Lists in Python are examples of iterable objects.

my_list = [1, 2, 3, 4, 5]
for i in my_list:

In the example above, my_list is an iterable, and the `for` loop is iterating over the values contained in it.

Now, consider this example with a string, another Python iterable:

my_string = "Zenva"
for char in my_string:

Though strings are not traditionally considered as collections, in Python, they are iterable as they can return their characters one at a time.

Working with Iterators

To understand iterators, let’s create one using Python’s built-in `iter()` function, which returns an iterator object.

my_list = [1, 2, 3, 4, 5]
my_iterator = iter(my_list)

In the above snippet, my_iterator is an iterator object created from my_list iterable. To access the next item in the iterator, we use the `next()` function.

print(next(my_iterator))  # Output: 1
print(next(my_iterator))  # Output: 2

For simplification, Python’s `for` loop implicitly creates an iterator from the given iterable and executes the `next()` function for you.

my_list = [1, 2, 3, 4, 5]
for i in my_list:

In the example above, Python is secretly doing something like this:

my_list = [1, 2, 3, 4, 5]
my_iterator = iter(my_list)

while True:
        i = next(my_iterator)
    except StopIteration:

Once all the elements in the iterator have been accessed, further calls to `next()` will raise a StopIteration exception, signaling that all elements have been processed.

So, by using iterators, Python allows you to traverse through all elements in the iterable in a clean, efficient way. It enables better memory management and cleaner code when working with large data sets. With the knowledge of iterable and iterator, you are now equipped to understand and better utilize many of Python’s built-in functionalities.

Adding An Iterable Behavior to Custom Objects

In Python, you’re not just limited to iterating over pre-defined iterables. With the magic of Python classes, you can make your own objects iterable. Here’s how it’s done:

class MyCollection:
    def __init__(self):
        self.items = []

    def add(self, value):

    def __iter__(self):
        return iter(self.items)

my_collection = MyCollection()

for item in my_collection:

In this case, we’ve created a custom collection class called MyCollection. It holds items, and we’ve defined an `add` method to append items to the collection. We’ve then implemented the `__iter__` method, which is a requirement for an object to be considered an iterable. This method returns an iterator that will iterate over its items.

Writing Your Custom Iterator

Apart from making your own iterable, Python also allows you to create your own iterators. Let’s create an iterator that gives us the Fibonacci sequence.

class Fib:
    def __init__(self, max):
        self.max = max

    def __iter__(self):
        self.a = 0
        self.b = 1
        return self

    def __next__(self):
        fib = self.a
        if fib > self.max:
            raise StopIteration
        self.a, self.b = self.b, self.a + self.b
        return fib

for i in Fib(100):

In the example above, we’ve created a custom iterator for generating a Fibonacci sequence up to a specified maximum. This iterator uses the `__next__` method, which is called to get the next value in the sequence, and the `__iter__` method, which simply returns self.

Built-In Python Functions for Working With Iterables

Python has numerous built-in functions designed for working with iterables. Here are a couple of examples:

my_list = [1, 2, 3, 4, 5]

# The built-in `sum()` function sums up elements of the iterable
print(sum(my_list))  # Output: 15

# The built-in `max()` function returns the item from the iterable with the highest value.
print(max(my_list))  # Output: 5

Understanding the inner working of iterable and iterator greatly enhances your proficiency with Python. As Python uses the concept of iterable and iterator extensively, you can now use Python more efficiently. So, keep practicing and keep exploring the endless possibilities with Python!

Continuing Your Learning Journey with Python

Having gotten a good grasp of Python’s iterable and iterator concepts, you are now equipped with advanced knowledge that can set apart your code from others. But the journey doesn’t stop here. Python is a vast language, with many more interesting and useful concepts to master.

Our Python Mini-Degree is an excellent stepping stone for programmers who are serious about being Python professionals. This in-depth program is a versatile collection of courses revolving around Python. Starting from fundamentals, it takes learners through various topics like object-oriented programming, game development, algorithms, app development and more.

What sets our mini-degree apart is the practical approach we adopt. We believe in learning by doing, hence students work on creating games, apps, chatbots, and a portfolio of Python projects.

  • Our instructors are experienced programmers, certified by industry-leading institutes.
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Python, with its simplicity and power, is a versatile tool that every programmer should aim to master. Understanding the depth of Python’s iterable and iterator concepts is a part of this significant process. With each line of code you write, you become more proficient, capable of solving complex problems and completing intricate projects. With a balance of theoretical learning and hands-on coding, we believe your journey with Python, and with us at Zenva, will be an enlightening and rewarding one.

Let the tenets of iterable and iterator guide you to writing more efficient and cleaner code. But the exploration doesn’t have to stop here. Join us in our Python Mini-Degree and continue growing your Python expertise. Other than just driving deeper into Python, you would be embarking on a journey of lifelong learning. Every step you take with us prepares you for real-world coding scenarios. Accelerate your programming journey by conquering one line of code at a time. Happy coding!

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