Flatten a nested list, Turn a nested list like [[1, 2], [3, 4]] into [1, 2, 3, 4].

Question

Anubhav Kumar · Answer

Problem Statement
Here are given a list that contains other lists inside it (one level deep). Our goal is to
combine all elements into a single flat list.
Approach
There are several ways to flatten a list in Python, especially for one-level deep nested lists. Here are two common approaches:
Method 1: 
Using List Comprehension (Recommended)
nested_list = [[1, 2], [3, 4]]
# Flattening the list using list comprehension
flat_list = [item for sublist in nested_list for item in sublist]
print(flat_list)
Explanation:
for sublist in nested_list: Loops through each sublist, e.g., 
[1, 2] and [3, 4].for item in sublist: Loops through each item inside that sublist.item for sublist in nested_list for item in sublist: This is a nested loop inside the list comprehension.
Output:
[1, 2, 3, 4]
Method 2: Using itertools.chain
import itertools
nested_list = [[1, 2], [3, 4]]
flat_list = list(itertools.chain.from_iterable(nested_list))
print(flat_list)
Explanation:
itertools.chain.from_iterable() takes an iterable of iterables and flattens it.You convert the result to a list using list().
Output:
[1, 2, 3, 4]
Use Case
This is useful when you are dealing with 2D data structures such as a grid, spreadsheet or nested data and you want a simple, one-dimensional idea.
Read More -
What are list comprehensions in Python?What is the difference between break, continue, and pass?What is the difference between mutable and immutable types in Python?

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Flatten a nested list, Turn a nested list like [[1, 2], [3, 4]] into [1, 2, 3, 4].

Anubhav Kumar

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1 Answers

Problem Statement

Approach

Method 1: Using List Comprehension (Recommended)

Explanation:

Method 2: Using `itertools.chain`

Explanation:

Use Case

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