Last Updated : 12 Jul, 2025
List comprehension and map() both transform iterables but differ in syntax and performance. List comprehension is concise as the logic is applied in one line while map() applies a function to each item and returns an iterator and offering better memory efficiency for large datasets.
List comprehensionList comprehension is a simple way to create new lists by applying transformations or filtering elements from an existing iterable. It is concise, readable, and ideal for simple operations.
Python
# Doubling each number in `li`
li = [1, 2, 3, 4]
res = [x * 2 for x in li]
print(res)
Explanation: [x * 2 for x in numbers] iterates through each item in li. and x * 2 applies the transformation to each element.
map() in pythonmap() function applies a specified function to each element of an iterable and producing a map object. The result can be converted to a list, tuple or other data structures if needed.
Python
# Doubling each number in `li`
li = [1, 2, 3, 4]
res = map(lambda x: x * 2, li)
print(list(res))
Explanation:
Here are some key differences between map and list comprehension.
Feature List Comprehension Map Function Syntax Concise and readable for simple transformations. Requires a function or lambda as the first argument. Readability Easy to read and understand for simple logic. Can become complex with lambdas for simple tasks. Output Type Directly produces a list. Returns an iterator (needs to be converted to a list). Performance Slightly slower for pre-defined functions. Faster for pre-defined functions due to optimizations. Memory Efficiency Creates a list in memory directly. Returns an iterator, which is memory efficient. Custom Logic Better for adding conditions or custom logic. Limited to the function provided. Use Case Simple or custom transformations with conditions. Applying pre-defined functions or handling large datasets.RetroSearch is an open source project built by @garambo | Open a GitHub Issue
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