Supercharge Python Data Engineering: Unleashing the Power of Generators

Dhruv Singhal
4 min readJul 7, 2023

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Generators in Python are an incredibly powerful tool that allows us to create iterators in a way that is both efficient and memory-friendly. They offer a more elegant solution compared to traditional functions by generating values on the fly, without the need to store them all in memory at once. In this article, we’ll explore the concept of generators, why and when to use them, and how they can be advantageous over regular functions in real-world programming scenarios.

Understanding Generators:

Generators are special functions that can be paused and resumed, giving us the ability to generate a sequence of values one at a time. Unlike regular functions, which return a value and terminate, generators use the yield keyword to produce values incrementally. They maintain their state between calls, making it possible to iterate over infinite sequences or generate values on demand.

Advantages of Generators:

Memory Optimization: Generators excel at optimizing memory usage. Unlike functions that generate an entire sequence upfront, generators generate and yield values as needed, resulting in lower memory consumption. This makes them well-suited for working with large datasets or even infinite sequences without overwhelming the system’s memory.

Efficiency and Performance: Generators shine in terms of efficiency and performance. Since they generate values on the fly, there’s no need to wait for the entire sequence to be calculated before processing. This significantly improves performance, especially when dealing with large datasets or computationally intensive tasks.

Enhanced Code Readability: One of the perks of using generators is that they lead to more readable and concise code. By employing the yield keyword, it becomes evident that the function is designed to produce a sequence of values. This improves code maintainability, readability, and reduces complexity.

Use Cases for Generators:

Processing Large Datasets: Generators are invaluable when working with large datasets that cannot fit into memory entirely. By iterating over the data in smaller chunks, generators enable efficient processing and prevent memory overflow issues.

Infinite Sequences and Streaming Data: Generators are a perfect fit for handling infinite sequences or streaming data. They allow us to generate an endless sequence of values, making them suitable for processing live data feeds, sensor data, or any continuous stream of information.

Data Transformation and Filtering: Generators are also handy for performing data transformation and filtering operations in a memory-efficient manner. By applying transformations on the fly, generators avoid the need to create intermediate lists or arrays, conserving memory and improving performance.

Code Examples:

Generating Fibonacci Sequence:

def fibonacci():
a, b = 0, 1
while True:
yield a
a, b = b, a + b

fibonacci_generator = fibonacci()
for i in range(10):
print(next(fibonacci_generator))

Explanation:

  1. The fibonacci() function is defined without any parameters. Inside the function, two variables a and b are initialized to 0 and 1 respectively. These variables will be used to generate the Fibonacci sequence.
  2. The while True: loop indicates an infinite loop that will keep generating Fibonacci numbers indefinitely.
  3. Inside the loop, yield a is used to yield the current value of a. The yield keyword is what makes this function a generator. It pauses the execution of the function, remembers its state, and returns a value. In this case, it returns the current Fibonacci number.
  4. After yielding a, the values of a and b are updated using the Fibonacci formula a, b = b, a + b. This swaps the values of a and b, and assigns the new value of a as the sum of the previous values of a and b.
  5. The Fibonacci generator is created by calling fibonacci() and assigning it to the variable fibonacci_generator.
  6. A for loop is used to iterate over a range of 10 numbers using range(10). This will execute the loop 10 times.
  7. Inside the loop, next(fibonacci_generator) is called to retrieve the next Fibonacci number from the generator. The next() function is used to advance the generator to its next state and return the yielded value.
  8. The yielded Fibonacci number is then printed using print().

Filtering Even Numbers:

def even_numbers(numbers):
for num in numbers:
if num % 2 == 0:
yield num

numbers_list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
even_numbers_generator = even_numbers(numbers_list)
for num in even_numbers_generator:
print(num)

Explanation:

Certainly! This code demonstrates the concept of a generator function that yields only the even numbers from a given list of numbers. Let’s break it down step by step:

  1. The even_numbers() function takes a list of numbers as input. It is defined to iterate over each number in the input list.
  2. Inside the function, an if statement is used to check if the current number (num) is divisible by 2, i.e., if it is an even number. The condition num % 2 == 0 checks if the remainder of dividing num by 2 is equal to 0, indicating that num is even.
  3. If the condition is true, yield num is executed. This means that the current num is yielded by the generator, effectively returning it as the next value in the sequence.
  4. The function continues to iterate over the numbers in the list, checking each one and yielding only the even numbers.
  5. The even_numbers() generator is created by calling even_numbers(numbers_list) and assigning it to the variable even_numbers_generator. The input to the generator function is the numbers_list list.
  6. A for loop is used to iterate over the even_numbers_generator. This loop will iterate through the even numbers generated by the generator.
  7. Inside the loop, each even number is assigned to the variable num.
  8. The even number num is then printed using the print() function.

Conclusion:

Generators in Python offer memory-efficient sequence generation and improve code efficiency. They are valuable for handling large datasets, infinite sequences, and data transformations, optimizing memory usage and performance. Embracing generators enhances Python programming effectiveness.

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Dhruv Singhal

Data engineer with expertise in PySpark, SQL, Flask. Skilled in Databricks, Snowflake, and Datafactory. Published articles. Passionate about tech and games.