--- title: Lesson 6: Functional Programming (FP) | daily.dev description: An introductory lesson on functional programming (FP) concepts in Python. Covers core FP principles including pure functions and immutability, then walks... canonical: https://daily.dev/posts/lesson-6-functional-programming-fp--9lu09yx71 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Lesson 6: Functional Programming (FP) | daily.dev og:description: An introductory lesson on functional programming (FP) concepts in Python. Covers core FP principles including pure functions and immutability, then walks... og:url: https://daily.dev/posts/lesson-6-functional-programming-fp--9lu09yx71 og:image: https://api.daily.dev/og/posts/9lu09YX71.png og:image:alt: Lesson 6: Functional Programming (FP) og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Lesson 6: Functional Programming (FP) **[Medium](https://daily.dev/sources/medium_js)** · 4 min read · 1 upvotes · 0 comments ## Summary An introductory lesson on functional programming (FP) concepts in Python. Covers core FP principles including pure functions and immutability, then walks through Python's FP toolkit: lambda functions, map(), and filter(). Concludes with a side-by-side comparison of map/filter versus list comprehensions, noting that list comprehensions are generally considered more Pythonic for simple operations. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the difference between using map() and filter() versus a list comprehension in Python? Both can produce the same result, but list comprehensions are generally considered more Pythonic and readable for simple transformations. For example, squaring even numbers from 1 to 10 can be written as a single list comprehension `[x*x for x in numbers if x % 2 == 0]`, compared to chaining `filter(lambda x: x % 2 == 0, numbers)` with `map(lambda x: x*x, evens)`. _Comparing idiomatic approaches like this is easier when daily.dev surfaces Python style discussions in one place._ ### What makes a function a pure function in functional programming? A pure function always returns the same output for the same input and produces no side effects, meaning it doesn't change anything outside itself. An example is `def add(a, b): return a + b`, which is predictable, contrasted with an impure function like `def add_random(a): return a + random.random()`, which produces different results each call. _Developers building predictable code often keep learning resources on functional programming close by through daily.dev._ ## Similar posts on daily.dev - [Using Functional Programming in Python – Real Python](https://daily.dev/posts/using-functional-programming-in-python-real-python-6enmbyrvx) · Real Python · 0 upvotes · 0 comments - [OOP vs Functional Programming Explained for Dummies](https://daily.dev/posts/oop-vs-functional-programming-explained-for-dummies-nnq1rp7ks) · Ruby Flow · 0 upvotes · 0 comments - [Lambda Days - Learning Resources / Talks - Erlang Forums](https://daily.dev/posts/lambda-days---learning-resources-talks---erlang-forums-hznvl5mu4) · Erlang Forums · 0 upvotes · 0 comments - [What's the Point of Learning Functional Programming?](https://daily.dev/posts/what-s-the-point-of-learning-functional-programming--fqrqaxolz) · Lobsters · 3 upvotes · 1 comments --- Tags: [#python](https://daily.dev/tags/python), [#functional-programming](https://daily.dev/tags/functional-programming) [View this post on daily.dev](https://daily.dev/posts/lesson-6-functional-programming-fp--9lu09yx71) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Lesson 6: Functional Programming (FP)","url":"https://daily.dev/posts/lesson-6-functional-programming-fp--9lu09yx71","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/lesson-6-functional-programming-fp--9lu09yx71"},"datePublished":"2026-07-23T05:08:28.318Z","dateModified":"2026-09-14T06:51:45.971Z","description":"An introductory lesson on functional programming (FP) concepts in Python. 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