What is Generator: Python For AI Explained




A python snake intertwined with a mechanical generator

In the world of Python programming, a generator is a unique construct that allows for the creation of iterable objects without the need to store all of the object’s values in memory at once. This is particularly useful in the field of Artificial Intelligence (AI), where datasets can be incredibly large and managing memory usage is critical.

Generators are a type of iterable, like lists or tuples. Unlike lists, they do not allow indexing with arbitrary indices, but they can still be iterated through with for loops. They are created using functions and the yield statement.

Understanding Generators

Before we delve into the specifics of generators, it’s important to understand the concept of iterables and iterators. In Python, an iterable is an object capable of returning its elements one at a time. Lists, tuples, strings, and dictionaries are all examples of iterables.

Iterators, on the other hand, are objects that define a method called __next__() which accesses elements in the iterable one at a time. When there are no more elements, it raises a StopIteration exception. An iterator can be created from an iterable by using the iter() function.

Creating a Generator

A generator in Python is created by defining a function as you normally would, but using the yield statement instead of return. The yield statement pauses the function and saves the local state so that it can be resumed right where it left off when next() is called again.

Here is a simple example of a generator function:

def simple_generator():
    yield 1
    yield 2
    yield 3

Using a Generator

To use a generator, you can use the next() function. This function allows you to access the next value in the sequence. Once all values have been accessed, a StopIteration exception is raised.

Here is an example of how to use the simple_generator function:

gen = simple_generator()
print(next(gen))  # Output: 1
print(next(gen))  # Output: 2
print(next(gen))  # Output: 3
print(next(gen))  # Raises StopIteration

Generators and Memory Management

One of the key benefits of generators is their ability to manage memory efficiently. When dealing with large datasets in AI, it’s not uncommon to encounter memory errors. This is where generators come in.

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Generators allow you to create a function that produces an iterable set of items, one at a time, in a particular way. Because of this, generators don’t have the memory restrictions that lists do. They can create an infinite stream of values.

Generators vs Lists

Let’s take a look at an example where we compare the memory usage of a list and a generator. Suppose we want to create a list of square numbers. Here’s how we might do it:

def squares(n):
    result = []
    for i in range(n):
        result.append(i * i)
    return result

Now, suppose we want to create a generator that produces the same sequence. Here’s how we might do it:

def squares(n):
    for i in range(n):
        yield i * i

In the first example, the entire list of squares is created and stored in memory before it’s returned. In the second example, the square numbers are generated one at a time, which means that at any given point, only one number is stored in memory.

Generators in AI

Generators are particularly useful in the field of AI. They allow you to create a pipeline for data processing, which can be extremely useful when dealing with large datasets.

For example, suppose you’re working with a dataset of images for a machine learning model. Instead of loading all the images into memory at once, you can use a generator to load and process them one at a time. This can significantly reduce your program’s memory footprint.

Example: Image Processing

Here’s an example of how you might use a generator to process images for a machine learning model:

def process_images(image_files):
    for image_file in image_files:
        image = load_image(image_file)
        image = preprocess_image(image)
        yield image

In this example, the process_images function is a generator that takes a list of image files, loads each one, processes it, and yields the processed image. This allows you to process a large number of images without loading them all into memory at once.


Generators are a powerful tool in Python, especially when working with large datasets in AI. They allow you to create efficient, memory-friendly programs that can handle large amounts of data.

Whether you’re processing images, analyzing text, or performing any other type of data-intensive task, generators can help you write more efficient and effective code. So the next time you’re faced with a large dataset, consider using a generator to handle it.

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