What is deep_flatten in Python..??

sanju saini
3 min readSep 28, 2024

--

Understanding deep_flatten in Python: Flattening Nested Iterables

When working with Python, you often encounter data structures like lists, tuples, and sets. Sometimes, these structures can be deeply nested, making it cumbersome to extract individual elements. Flattening a nested structure refers to transforming it into a single-level sequence where all the inner components are extracted and placed in one iterable, such as a list or a tuple.

Python provides various ways to flatten such structures, but handling deeply nested ones can take time and effort. This is where the deep_flatten function, often found in third-party libraries, comes into play.

What is deep_flatten?

deep_flatten is a function that recursively flattens an iterable, regardless of how deeply nested it is. Deep flattening involves flattening multiple levels of nested tables (like lists of lists, lists of tuples, etc.) into a one-dimensional sequence.

Example of Deep Flattening in python

nested_list = [1, [2, [3, 4], 5], 6]
flattened = deep_flatten(nested_list)
print(list(flattened))

Output:

[1, 2, 3, 4, 5, 6]

In this example, deep_flatten transforms the nested list into a single flat list containing all the individual elements.

Implementing deep_flatten in Python

While Python doesn’t have a built-in deep_flatten function, you can implement it using recursive techniques.

Here’s a simple implementation:

def deep_flatten(iterable):
for item in iterable:
if isinstance(item, (list, tuple, set)):
yield from deep_flatten(item)
else:
yield item

How It Works

  • Recursion: If the current item is iterable (like a list, tuple, or set), the function recursively calls itself to process the sub-elements.
  • yield from: This statement helps in yielding elements from the inner iterable (thresult of the recursive call).
  • Base Case: If the item is not an iterable, it is yielded directly.

Example Usage

nested_structure = [1, [2, [3, [4, 5]], 6], 7, [8, 9]]
flattened = deep_flatten(nested_structure)
print(list(flattened))

Output:

[1, 2, 3, 4, 5, 6, 7, 8, 9]

Why Use deep_flatten?

  1. Simplifies Data Handling: You no longer need to manually loop through multiple levels of nested structures.
  2. Flexible: It works with various iterable types like lists, tuples, and sets.
  3. Readability: Your code becomes cleaner and more maintainable, especially when dealing with complex nested data.

Using deep_flatten External Libraries

Some Python libraries, such as more_itertools, offer built-in solutions for deep flattening.

Example with more_itertools

First, install the library:

pip install more-itertools

Now, you can use deep_flatten directly:

from more_itertools import deep_flatten
nested_list = [1, [2, [3, 4], 5], 6]
flattened = list(deep_flatten(nested_list))
print(flattened)p

Output:

[1, 2, 3, 4, 5, 6]

Key Considerations

  • Non-iterable types: If your nested structure contains non-iterable types like integers, strings, or floats, ensure your deep_flatten function handles them correctly by yielding the values directly instead of attempting to iterate over them.
  • Performance: Deep flattening can become computationally expensive for very large and complex structures. If performance is a concern, test the function on smaller datasets before using it on a large scale.

Conclusion

Flattening deeply nested structures is a common problem in Python programming. While there’s no built-in function to handle deep flattening, writing your own deep_flatten function is straightforward, and there are external libraries like more_itertools that can help.

Whether you choose to implement it yourself or leverage external libraries, deep_flatten is a powerful tool for dealing with complex data structures in Python.

Connect with Me

--

--

sanju saini
sanju saini

Written by sanju saini

Senior Software Engineer with 4.5+ years of experience in full-stack development, specializing in Python, Golang, PHP, Django, FastAPI, React, and RESTful APIs.

No responses yet