Python Fundamentals: Data Types, Conversion, and Operators

Most people learning Python struggle with one thing: Classes. This is not due to how class definitions function or their complexity, but is mainly because they are typically explained in a complicated fashion. I recently shared an article where I break down Python classes in the simplest way possible — from basics to intuition, without unnecessary jargon. Furthermore, understanding class definitions is important in Python and as such is also a requirement when writing scalable/dependable systems. If you're learning Python or transitioning into ML, this will make things much clearer. What concept in Python took you the longest to truly understand? ♻️ Repost if you’re betting on yourself this time. ➕ Follow me, Samith Chimminiyan, for such ML-related content.  Learning in public 🚀 #Python #MachineLearning #DataScience #Programming #OOP #LearnToCode #Developers

python study day 12 1. Basics of Functions A function is a reusable block of code that performs a specific task when called. Functions are useful to organize code, make it reusable, and reduce redundancy. 2. Defining a Function You define a function using the def keyword followed by the function name, parentheses, and a colon :. Syntax: def function_name(parameters): # Block of code Example: Basic function to greet a user def greet(): print("Hello! Welcome to the Python course.") greet() Output: Hello! Welcome to the Python course. 3. Function Parameters Parameters are variables used to pass data into a function. Example: Function with a parameter def greet_user(name): print(f"Hello, {name}! Welcome to the Python course.") greet_user("Anand") Output: Hello, Anand! Welcome to the Python course. 4. Returning Values from a Function A function can return a value using the return keyword, which allows the output of the function to be reused elsewhere. Example: Function that adds two numbers and returns the result def add_numbers(a, b): return a + b result = add_numbers(10, 20) print("The sum is:", result) Output: The sum is: 30 5. Default Parameter Values You can define a default value for a parameter, which is used if no argument is passed when the function is called. Example: Function with a default parameter def greet(name="Student"): print(f"Hello, {name}! Welcome to the Python course.") greet() # Uses default value "Student" greet("Geetha") # Uses passed value "Geetha" Output: Hello, Student! Welcome to the Python course. Hello, Geetha! Welcome to the Python course. Here are the sections for Nested Functions and Local/Global Variables: 6. Local and Global Variables Local Variables are defined inside a function and are only accessible within that function. Global Variables are defined outside all functions and are accessible from anywhere in the code. Example: Local vs Global variables name = "Global Name" def greet(): name = "Local Name" print(name) greet() # Prints local variable print(name) # Prints global variable Output: Local Name Global Name In this example, the local variable name inside the function does not affect the global variable name.

🚀 Excited to share my latest blog! As a beginner in Python, I often felt confused about when to use lists, tuples, sets, or dictionaries So, I created a simple and practical guide: Choosing the Right Python Data Structure: A Beginner’s Decision Guide In this blog, I explained: ✔ Differences between list, tuple, set, and dictionary ✔ When to use each data structure ✔ Real-world examples for better understanding This helped me clearly understand how to select the right data structure instead of guessing. 🔗 Read my blog here: https://lnkd.in/dnBzV4VS Would love your feedback #Python #DataStructures #Programming #Beginners #Coding #LearningInPublic #Internship Innomatics Research Labs

What is the use of self in Python? If you are working with Python, there is no escaping from the word “self”. It is used in method definitions and in variable initialization. The self method is explicitly used every time we define a method. The self is used to represent the instance of the class. With this keyword, you can access the attributes and methods of the class in python. It binds the attributes with the given arguments. The reason why we use self is that Python does not use the ‘@’ syntax to refer to instance attributes self is used in different places and often thought to be a keyword. But unlike in C++, self is not a keyword in Python. self is a parameter in function and the user can use a different parameter name in place of it. Although it is advisable to use self because it increases the readability of code. In Python, self is the keyword referring to the current instance of a class. Creating an object from a class is actually constructing a unique object that possesses its attributes and methods. The self inside the class helps link those attributes and methods to a particular created object. Self in Constructors and Methods self is a special keyword in Python that refers to the instance of the class. self must be the first parameter of both constructor methods (__init__()) and any instance methods of a class. For a clearer explanation, see this: When creating an object, the constructor, commonly known as the __init__() method, is used to initialize it. Python automatically gives the object itself as the first argument whenever you create an object. For this reason, in the __init__() function and other instance methods, self must be the first parameter. If you don’t include self, Python will raise an error because it doesn’t know where to put the object reference. Is Self a Convention? In Python, instance methods such as __init__ need to know which particular object they are working on. To be able to do this, a method has a parameter called self, which refers to the current object or instance of the class. You could technically call it anything you want; however, everyone uses self because it clearly shows that the method belongs to an object of the class. Using self also helps with consistency; hence, others-and, in fact, you too-will be less likely to misunderstand your code. Why is self explicitly defined everytime? In Python, self is used every time you define it because it helps the method know which object you are actually dealing with. When you call a method on an instance of a class, Python passes that very same instance as the first argument, but you need to define self to catch that. By explicitly including self, you are telling Python: “This method belongs to this particular object.” What Happens Internally when we use Self? When you use self in Python, it’s a way for instance methods—like __init__ or other methods in a class—to refer to the actual object that called the method. #Python #Data_analaysis

Day 10 of my Python journey — functions. If I had to choose the single most important concept in software engineering, it would be this: write small, focused, well-named functions. Not because it is a rule. Because it is the only practical way to manage complexity as programs grow larger. A 20-line program can be understood by reading it top to bottom. A 2,000-line program cannot — unless it is broken into functions, each doing one clear thing, each named for what it does, each testable independently. *args and **kwargs — why every Python developer needs to understand these def print_scores(*names):   for name in names:     print(f"Score recorded for: {name}") print_scores("Rahul")            # Works print_scores("Rahul", "Priya", "Arjun")   # Also works *args collects any number of positional arguments into a tuple. **kwargs collects any number of keyword arguments into a dictionary. When you call print("a", "b", "c", sep=", ") — that works because print uses *args. When Flask's @app.route("/path", methods=["GET"]) accepts options — that is **kwargs. When requests.get(url, timeout=5, verify=False) takes optional parameters — **kwargs again. Understanding these means understanding how every Python library and framework is designed from the inside. The mutable default argument trap — a famous Python gotcha # DANGEROUS — this is a silent bug def add_task(task, task_list=[]):   task_list.append(task)   return task_list add_task("Buy groceries") # ["Buy groceries"] — correct add_task("Call dentist")  # ["Buy groceries", "Call dentist"] — WRONG The default list is created once when the function is defined. Every call shares the same list. This is one of the most well-known bugs in Python — and I learned it on Day 10. The correct approach: def add_task(task, task_list=None): then task_list = task_list or []. Docstrings — the habit I build from today def calculate_gst(amount: float, rate: float = 0.18) -> float:   """Calculate GST on a given amount.   Args: amount (float): base price. rate (float): GST rate, default 18%.   Returns: float: the GST amount to add."""   return amount * rate Every function I write from now on has a docstring. IDEs read them for autocomplete. Documentation generators build API docs from them. Code reviewers judge them. Professional habit, built from Day 10. Functions are the architecture of every program worth reading. #Python#Day10#ConditionalLogic#SelfLearning#CodewithHarry#PythonBasics#w3schools.com#W3Schools

If you already know Python basics and you’re still writing slow, repetitive, and inefficient code… Then you’re not stuck You’ve just not learned Advanced Python Operations yet I just released a session on “Advanced Python Operations for Machine Learning Beginners” and this is where things start to separate beginners from serious builders. Because this is the stage where Python stops being “just code” And becomes a tool for speed, efficiency, and real-world problem solving ⸻ 1. You stop writing long code and start writing smart code At this level, it is not about doing more It is about doing things better You begin to use: List comprehensions Lambda functions Ternary operations Instead of writing 10 lines, you write 2 clean lines that do the same thing That is how professionals think ⸻ 2. You understand how Python actually works under the hood Most beginners use Python Few understand it Here you start learning: Iterators and generators Memory efficiency How loops really execute This is critical when working with large datasets especially in health research where data can be massive ⸻ 3. You master vectorization and stop using slow loops This is a big shift Instead of looping through data manually, you use: NumPy operations Pandas vectorization This alone can make your code 10x faster And in data science, speed is not luxury It is necessity ⸻ 4. You write reusable and scalable code Now you are thinking like a system builder You start using: Functions properly Modular code structure Reusable pipelines Because in research and machine learning, you will run the same process multiple times Efficiency matters ⸻ 5. You handle data like a pro At this stage, your data manipulation becomes sharper You are now comfortable with: Advanced filtering Groupby operations Merging and joining datasets Handling complex missing data This is the real backbone of machine learning work ⸻ 6. You begin to think in workflows, not just scripts Beginners write scripts Advanced users design workflows You now understand: Data pipeline thinking Step by step transformation Reproducibility in research And this is exactly what separates academic work from impactful research ⸻ 7. You move closer to real machine learning Advanced Python operations are the bridge Between: “I can code” And “I can build models that solve problems” Without this level, machine learning becomes guesswork With it, everything becomes structured and intentional Link https://lnkd.in/eK3CDZFT

🚀 Day 8 of Learning Python: Error Handling 💻 ✅ Back with a learning update 👉 Today I explored how Python handles errors gracefully using exception handling. This helps prevent programs from crashing and improves user experience. 🔹 Common Python Errors: ZeroDivisionError → Dividing by zeroValueError → Invalid input (e.g., text instead of number)TypeError → Wrong data type usedFileNotFoundError → File does not exist 💡 1. Simple Error Handling try: num = int(input("Enter number: ")) print(10 / num) except: print("Error occurred!")👉 Prevents the program from crashing on invalid input 💡 2. Handling Specific Errors try: num = int(input("Enter number: ")) print(10 / num) except ZeroDivisionError: print("Cannot divide by zero!") except ValueError: print("Please enter a valid number!") 💡 3. Using else try: num = int(input("Enter number: ")) except ValueError: print("Invalid input") else: print("You entered:", num)👉 else runs only when no exception occurs 💡 4. Using finally try: file = open("data.txt") except FileNotFoundError: print("File not found!") finally: print("Execution completed")👉 finally always executes (useful for cleanup) 💡 5. Handling Multiple Errors Together try: a = int(input()) b = int(input()) print(a / b) except (ValueError, ZeroDivisionError): print("Invalid input or division by zero") ⚡ Raising Your Own Error age = int(input("Enter age: ")) if age < 18: raise Exception("You must be 18+") 🔥 Custom Exception (Advanced) class MyError(Exception): pass try: raise MyError("Something went wrong") except MyError as e: print(e) ✅ Key Takeaway: Error handling makes your programs more robust, user-friendly, and professional. #Python #CodingJourney #LearnPython #30DaysOfCode #Programming

🐍 3 Python Built-ins That Look Simple… But Are More Powerful Than They Seem One thing I appreciate about Python is how some of the most useful tools look deceptively simple. At first glance, they seem basic. But once you understand the one feature that really matters, they become incredibly practical in real projects. Here are 3 built-ins that quietly make Python code cleaner and more expressive. 🔢 1. sorted() — More Than Just Sorting Numbers Most people think sorted() is mainly for sorting numbers or strings. But the real power comes from key=. In real applications, you're rarely sorting plain numbers. Instead, you're sorting things like: 👤 Users 📋 Tasks 📁 Files 📦 Dictionaries The key parameter tells Python which part of each item should determine the order. Examples in real projects: ✔️ Sort users by age ✔️ Sort tasks by priority ✔️ Sort files by modification date Instead of restructuring your data or writing extra logic, sorted() lets you clearly express how your data should be ordered. 🔗 2. zip() — Pair Related Data Cleanly A very common pattern looks like this: names[i] ages[i] It works… but it also means manually managing indexes. zip() removes that extra work. It lets you iterate through related values together, without worrying about positions. Example scenarios: 👤 Names + ages 🛒 Products + prices 📅 Dates + sales numbers Another benefit: if the lists have different lengths, zip() automatically stops at the shortest one. The result? ✔️ Less indexing ✔️ Cleaner loops ✔️ Easier-to-read code 🔁 3. enumerate() — When You Need Index + Value You’ve probably seen this pattern before: for i in range(len(items)): It works, but it’s not the cleanest approach. enumerate() already gives you both the index and the value in one step. This makes loops much more natural. Common use cases include: 📋 Printing numbered lists 📊 Tracking item positions 🧭 Working with ordered data A small change—but it often makes loops simpler and clearer. 💡 The Bigger Lesson Many Python built-ins are like this. They look simple at first, so people only use them at a surface level. But once you understand the feature that really matters, your code becomes: ✔️ clearer ✔️ shorter ✔️ easier to reason about And that’s a pretty good trade. 💬 Which Python built-in improved your code the most once you truly understood it? #Python #Programming #SoftwareEngineering #PythonTips #CleanCode #DeveloperProductivity #CodingTips

Start learning Python by writing code. Not by watching tutorials. Not by saving playlists. Actually writing code. Because Python looks simple on the surface… but the real value comes when you start using it. Most people stop at basics like: print statements   loops   if-else  And then say “I know Python.” But real understanding starts when you go deeper. When you learn things like: • how data structures actually behave   • how functions organize logic   • how OOP helps structure real systems   • how APIs, files, and databases connect to code   • how automation and scripting solve real problems  That’s when Python starts becoming useful. This PDF is helpful because it doesn’t just show syntax. It walks through Python step-by-step — from fundamentals to real-world concepts like APIs, file handling, multithreading, and more. :contentReference[oaicite:0]{index=0} So instead of jumping between random tutorials, you can build understanding in one structured flow. A simple way to use it: 1. Pick one concept   2. Write code for it   3. Modify it and break it   4. Try to apply it in a small use case  That’s how skills actually stick. Because Python is not about knowing everything. It’s about being able to use it when needed. And that only happens through practice. Not passive learning. Save this sheet so you can revisit it while practicing. Comment "Python" and I’ll send the full PDF. Follow Sahil Hans for daily tech job openings and practical interview prep resources that make switching easier.