140+ Basic Python Programs for Beginners and Interviews

🚀 Day 5 of My LeetCode Journey – Solved Contains Duplicate! 💻✨ Today I solved LeetCode #217 – Contains Duplicate ✅ A popular Easy-level array problem often asked in coding interviews. 📌 Problem Statement Given an integer array nums, return true if any value appears at least twice in the array, otherwise return false. Example: nums = [1,2,3,1] ✅ Output: true 🔍 My Approach – Using Set I used Python’s built-in set() for an efficient solution. Convert the array into a set Compare the length of the original array with the set If lengths are different → duplicates exist Otherwise → all elements are unique 💡 Why This Works A set stores only unique elements, so any duplicate values are automatically removed. This made the solution short, clean, and optimized 🚀 💡 What I Learned This problem helped me strengthen: ✔ Arrays ✔ Hashing / Set usage ✔ Python built-in functions ✔ Efficient duplicate detection ✔ Interview coding logic ⏱ Complexity Time Complexity: O(n) Space Complexity: O(n) Small problems like this are great for building strong DSA fundamentals 🔥 #LeetCode #Python #DSA #Arrays #Hashing #ProblemSolving #CodingJourney #SoftwareDeveloper #InterviewPreparation #Programming #100DaysOfCode #LearningInPublic

Day 63 of my #100DaysOfCode challenge 🚀 Today I worked on generating all permutations of a string using recursion in Python. This is a fundamental problem to understand recursion + backtracking patterns, and it's very common in coding interviews. What the program does: • Takes a string as input • Generates all possible permutations • Uses recursive approach (no built-ins like itertools) • Returns all arrangements of characters Example (Input: "abc"): Permutations:['abc', 'acb', 'bac', 'bca', 'cab', 'cba'] Total permutations: 6 How the logic works: Recursive idea: 1. Fix one character at a time 2. Find permutations of remaining string 3. Combine fixed character with each permutation 4. Repeat until only one character is left Example breakdown: Fix 'a' → permute "bc" Fix 'b' → permute "ac" Fix 'c' → permute "ab" Why this is important: – Core concept for recursion & backtracking – Used in problems like: Anagrams Password generation Combination problems – Frequently asked in interviews – Builds strong problem-solving mindset Time Complexity: O(n!) Space Complexity: O(n!) Key Takeaways: – Recursive problem decomposition – Understanding permutations logic – Building solutions step-by-step – Avoiding built-in shortcuts for clarity #100DaysOfCode #Day63 #Python #Programming #Recursion #Backtracking #Permutations #Strings #Algorithms #DSA #CodingPractice #ProblemSolving #InterviewPrep #LearnByDoing #DeveloperJourney #Consistency #BTech #CSE #AIandML #VITBhopal #TechJourney

𝗠𝗼𝘀𝘁 𝗽𝗲𝗼𝗽𝗹𝗲 “𝗹𝗲𝗮𝗿𝗻” 𝗣𝘆𝘁𝗵𝗼𝗻. 𝗩𝗲𝗿𝘆 𝗳𝗲𝘄 𝗳𝗲𝗲𝗹 𝗰𝗼𝗻𝗳𝗶𝗱𝗲𝗻𝘁 𝘂𝘀𝗶𝗻𝗴 𝗶𝘁. That’s the difference between knowing concepts… and building solutions. You don’t need more tutorials. 𝗬𝗼𝘂 𝗻𝗲𝗲𝗱 𝗰𝗹𝗮𝗿𝗶𝘁𝘆. 𝗠𝗼𝘀𝘁 𝗽𝗲𝗼𝗽𝗹𝗲: Watch tutorials Complete courses Understand basics 𝗔𝗻𝗱 𝘀𝘁𝗶𝗹𝗹 𝗴𝗲𝘁 𝘀𝘁𝘂𝗰𝗸. When it’s time to build. 𝗧𝗵𝗮𝘁’𝘀 𝘁𝗵𝗲 𝗿𝗲𝗮𝗹 𝗽𝗿𝗼𝗯𝗹𝗲𝗺. Not Python. 𝗡𝗼 𝗳𝗼𝗰𝘂𝘀. 𝗦𝗼𝗹𝘂𝘁𝗶𝗼𝗻: 𝗔 𝗰𝗹𝗲𝗮𝗿 𝗣𝘆𝘁𝗵𝗼𝗻 𝗰𝗵𝗲𝗮𝘁 𝘀𝗵𝗲𝗲𝘁. 𝗙𝗼𝗰𝘂𝘀 𝗼𝗻: Core syntax Data structures Functions & loops Real-world patterns 𝗡𝗼𝘁 𝗲𝘃𝗲𝗿𝘆𝘁𝗵𝗶𝗻𝗴. 𝗝𝘂𝘀𝘁 𝘁𝗵𝗲 𝗿𝗶𝗴𝗵𝘁 𝘁𝗵𝗶𝗻𝗴𝘀. 𝗥𝗲𝗮𝗹 𝗴𝗮𝗺𝗲: Learning → Easy 𝗨𝘀𝗶𝗻𝗴 → 𝗦𝗸𝗶𝗹𝗹 𝗞𝗲𝘆 𝗶𝗻𝘀𝗶𝗴𝗵𝘁: Confidence doesn’t come from knowing more. 𝗜𝘁 𝗰𝗼𝗺𝗲𝘀 𝗳𝗿𝗼𝗺 𝗿𝗲𝗽𝗲𝗮𝘁𝗶𝗼𝗻. Spend less time searching. Spend more time solving. 𝗖𝗼𝗻𝗻𝗲𝗰𝘁 𝘄𝗶𝘁𝗵 𝗺𝗲 𝗖𝗼𝗺𝗺𝗲𝗻𝘁 𝗶𝗳 𝘆𝗼𝘂 𝘄𝗮𝗻𝘁 𝘁𝗵𝗲 𝗳𝘂𝗹𝗹 𝗰𝗵𝗲𝗮𝘁 𝘀𝗵𝗲𝗲𝘁 #Python #DataEngineering #TechCareers #InterviewPrep #Developers

🔤 Master Python String Functions — A Must for Beginners! 🐍 Strings are everywhere in programming — from user inputs to API responses. If you're learning Python, understanding string functions can seriously level up your coding game 🚀 Here’s a quick breakdown 👇 ✨ 1. Case Conversion Convert text easily: upper(), lower(), title(), capitalize(), swapcase() 🔍 2. Search & Find Locate words inside strings: find(), index(), startswith(), endswith() ✂️ 3. Modify Strings Clean and update text: replace(), strip(), lstrip(), rstrip() 🔗 4. Split & Join Transform data structures: split() → string ➝ list join() → list ➝ string ✅ 5. Check Methods (True/False) Validate input quickly: isalpha(), isdigit(), isalnum(), isspace() 📏 6. Formatting & Alignment Make output look clean: center(), ljust(), rjust(), zfill(), format() 💡 Pro Tip: Python has 40+ string methods — you don’t need to memorize all. Focus on understanding when to use what 👍 🎯 Whether you're preparing for interviews or building real projects, string handling is a core skill you can't skip. 💬 Which string method do you use the most? #Python #Programming #Coding #PythonForBeginners #Developers #Learning #Tech #SoftwareDevelopment #AutomationTesting

🧠 Building consistency, one concept at a time. 📅 Day 6 of my Python Journey Today was all about strengthening core fundamentals and taking a step closer to writing structured, efficient code. 💡 What I worked on today: 🔁 While Loops Practiced control flow using while loops. Solved multiple logic-building problems like: Reversing a number. Checking palindrome numbers. Digit-based operations. ⚙️ Functions Learned how to break problems into reusable blocks. Practiced writing clean and modular code. 🧩 Types of Arguments Explored different ways to pass values into functions. Understood flexibility in function design. 📦 Started Data Structures in Python – Lists After functions, I moved into in-built data structures, starting with Lists. From the practice files today, I covered: ✔️ Basics of list creation and manipulation ✔️ Hands-on with in-built methods like: append(), insert(), extend() remove(), pop(), del index(), count() sort(), reverse(), copy(), clear() Also explored how nested lists can be used to represent 2D structures like matrices. 🚀 What’s next? Moving forward, I’ll be solving problem-based questions on lists to strengthen my understanding and logic. 📌 Key Insight: It’s not just about learning syntax… It’s about understanding how and where to use it effectively. Consistency is building. Clarity is improving. And that’s what matters. #Python #Day6 #CodingJourney #DataStructures #LearningInPublic #ProblemSolving #Developers #TechGrowth #SDE #Programming

I spent hours writing this by hand so you don't have to spend days googling 🐍✍️ Here's your complete Python Cheatsheet — from beginner to intermediate — all in ONE page: ✅ Variables & Data Types ✅ Lists, Tuples, Dicts & Sets ✅ Control Flow (if/for/while) ✅ Functions & Lambda ✅ List Comprehension ✅ Exception Handling ✅ OOP Basics ✅ File Handling ✅ 12+ Useful Built-ins Save this post 🔖 — you'll thank yourself later. If you're learning Python or brushing up before an interview, this is all you need to get started. Drop a "🐍" in the comments if this helped you! Follow me for more handwritten tech notes every week 👇 #Python #PythonProgramming #LearnPython #CodingTips #Programming #100DaysOfCode #TechTwitter #Developer #SoftwareEngineering #PythonCheatsheet #CodeNewbie #LinkedInLearning

Most developers spend months watching tutorials. I learned more by building real Python projects in a single weekend. This article shares the exact projects that shifted my mindset from *learning code* to *solving problems*. Because in tech, progress doesn’t come from theory it comes from execution. If you're serious about growing in Python, start building. Today. #Python #AI #Projects #LearningByDoing #CareerGrowth

Struggling with subarray problems? This one pattern can solve most of them 👇 If you’re preparing for coding interviews or improving your problem-solving skills, the Prefix Sum technique is a must-know pattern. 💡 What is Prefix Sum? It’s a way to store the cumulative sum of elements so that you can quickly calculate the sum of any subarray in constant time. 👉 Example: For array [1, 2, 3, 4] Prefix sum becomes → [1, 3, 6, 10] 🎯 Why use it? . Reduces time complexity from O(n²) → O(n) . Helps solve problems like: - Subarray sum = k - Longest subarray with given sum - Count of subarrays 🧠 Core Idea: Instead of recalculating sums again and again: sum(i to j) = prefix[j] - prefix[i-1] 🔥 Power Boost with HashMap Combine prefix sum with a hashmap to: - Track previously seen sums - Solve complex problems in one pass ⚡ Key Patterns to Remember: - currentSum += nums[i] - Check currentSum - k - Store sum in hashmap - For longest → store first occurrence - For count → store frequency 💬 Learning Tip: Don’t just memorize the code — understand why we store sums and how we use them. 📌 Prefix Sum is not just a trick — it’s a pattern that appears again and again in interviews. Keep practicing. Keep improving. 💪 #DSA #CodingInterview #Programming #Python #SoftwareEngineering #Learning #100DaysOfCode

❌ 90% of Python Beginners Get This WRONG… 👉 Difference between SET and DICTIONARY Think you know it? Let’s test 👇 . 💡 SET vs DICTIONARY (Real Interview Answer) 🔹 SET ✔️ Stores only values ✔️ No duplicates allowed ✔️ Unordered collection . Example: {1, 2, 3} 🔹 DICTIONARY ✔️ Stores key-value pairs ✔️ Keys must be unique ✔️ Ordered (Python 3.7+) . Example: {"a": 1, "b": 2} 💥 The REAL Difference (Important 🔥) 👉 Set = Only values 👉 Dictionary = Key + Value 👉 Set = Used for uniqueness 👉 Dictionary = Used for mapping data . ⚡ Pro Tip (Interview Level): If you explain with a real-world example, you stand out instantly 💯 Example: Set → Unique user IDs Dictionary → User ID → User Details . 📌 Save this before your next interview 💬 Comment "PYTHON" for more questions 🔁 Share with your friends 🔥 Follow for daily coding & interview content . #Python #PythonDeveloper #Coding #Programming #Developers #SoftwareDeveloper #PythonInterview #CodingInterview #LearnPython #Tech #DeveloperCommunity #SoftwareEngineering #BackendDeveloper #FullStackDeveloper #TechCareers #ITJobs #CareerGrowth #CodeDaily #ProgrammingTips #100DaysOfCode #DevelopersLife #InterviewPreparation #TechEducation #linkedinlearning

🚀 𝐏𝐲𝐭𝐡𝐨𝐧 𝐍𝐨𝐭𝐞𝐬 𝐭𝐡𝐚𝐭 𝐞𝐯𝐞𝐫𝐲 𝐁𝐞𝐠𝐢𝐧𝐧𝐞𝐫 𝐬𝐡𝐨𝐮𝐥𝐝 𝐬𝐚𝐯𝐞 If you're starting your journey in Python, this is your complete roadmap 👇 💡 𝐖𝐡𝐚𝐭 𝐲𝐨𝐮’𝐥𝐥 𝐥𝐞𝐚𝐫𝐧: 📌 𝐁𝐚𝐬𝐢𝐜𝐬 → Variables, Data Types, Syntax 🔤 𝐒𝐭𝐫𝐢𝐧𝐠𝐬 & 𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐨𝐧𝐬 → Indexing, slicing, functions 🔢 𝐃𝐚𝐭𝐚 𝐓𝐲𝐩𝐞𝐬 → int, float, bool, type casting ⚙️ 𝐎𝐩𝐞𝐫𝐚𝐭𝐨𝐫𝐬 → Arithmetic, relational, logical 🔁 𝐂𝐨𝐧𝐝𝐢𝐭𝐢𝐨𝐧𝐬 → if, else, elif (real examples) 📥 𝐔𝐬𝐞𝐫 𝐈𝐧𝐩𝐮𝐭 → input(), type conversion 📚 𝐃𝐢𝐜𝐭𝐢𝐨𝐧𝐚𝐫𝐢𝐞𝐬 → keys(), values(), items() 🔥 𝐖𝐡𝐲 𝐭𝐡𝐢𝐬 𝐢𝐬 𝐠𝐨𝐥𝐝? Because everything is explained in simple handwritten notes + examples Perfect for beginners & revision 💬 𝐓𝐢𝐩: Don’t just read Python ❌ 👉 Write code 👉 Make mistakes 👉 Fix them That’s how you become a real developer 💻 📌 Save this if you're learning Python / Programming Follow me for more simple & powerful tech content 🚀 #Python #Programming #Coding #LearnPython #DataScience #AI #TechCareers #Beginners #SoftwareDevelopment #CareerGrowth