Python-Essentials-1

Module 1

1.0 Welcome to Python Essentials 1

1.0.1 Learn Python – the language of today and tomorrow
1.0.2 About the course
1.0.3 Syllabus
1.0.4 Prepare for the PCEP-30-0x exam

1.1 Section 1 – Introduction to Programming

1.1.1 How does a computer program work?
1.1.2 Natural languages vs. programming languages
1.1.3 What makes a language?
1.1.4 Machine language vs. high-level language
1.1.5 Compilation vs. Interpretation

1.2 Section 2 – Introduction to Python

1.2.1 Python – a tool, not a reptile
1.2.2 Who created Python?
1.2.3 A hobby programming project
1.2.4 What makes Python so special?
1.2.5 Python rivals?
1.2.6 Where can we see Python in action?
1.2.7 Why not Python?
1.2.8 There is more than one Python
1.2.9 Python implementations

1.3 Section 3 – Downloading and Installing Python

1.3.1 Begin your Python journey
1.3.2 How to download, install, and configure Python
1.3.3 Starting your work with Python
1.3.4 Your very first program before your first program...
1.3.5 How to spoil and fix your code

Note:- CPython kya hai?

CPython is the implementation of Python language — basically, it’s the actual software that runs your Python code.

CPython is written in C language, iska naam bhi isi wajah se "CPython" rakha gaya hai.

Jab aap terminal me python ya python3 likh ke code run karte ho, toh aap asal me CPython interpreter hi chala rahe hote ho.

Ye implementation Python ke rules (syntax, behavior) ko follow karta hai — jaise PSF (Python Software Foundation) ne define kiya hai.

💡 Think of CPython as the engine that powers your Python programs.

Note:- Python 2

print "Hello World"  # No parentheses

Note:- Python 3

print("Hello World")  # Parentheses required

Note :- CPython kya hai

CPython is the original and official implementation of the Python programming language.
It is written in the C language and maintained by the Python Software Foundation (PSF).
Jab aap terminal me python ya python3 likhte ho, aap mostly CPython hi chala rahe hote ho.
Ye sabse stable, popular aur widely supported version hai

Note :-

💬 Summary in One Line Each:
✅ CPython – Official and most-used Python interpreter.

🚀 Cython – Make Python code faster by compiling to C.

☕ Jython – Use Python in Java apps (runs on JVM).

⚡ PyPy – Fastest Python using Just-in-Time compiler.

🧩 MicroPython – Run Python on small hardware devices (IoT).

Python Implementations Comparison

Implementation	Purpose / Use Case	Special Features	Example
CPython (C-language Python)	✅ Most commonly used and official version of Python ✅ Suitable for everyday development like web development, scripting, automation, etc.	🔹 Written in C programming language 🔹 Maintained by Python Software Foundation (PSF) 🔹 Supports almost all Python libraries and tools	📌 Basic Python usage: print("Hello from CPython") 📌 Used in: Django, Flask, Jupyter, etc.
Cython (C-Extension Python)	✅ Used to increase performance of Python code, especially useful in scientific computing, loops, data processing, and machine learning	🔹 Converts Python code into C language for speed 🔹 Offers optional static typing 🔹 Helps write hybrid Python + C programs	📌 Example (Cython function): cython<br>cpdef int fast_square(int x):<br> return x * x 📌 Used in: Pandas, Scikit-learn, NumPy
Jython (Java Python)	✅ Lets you write Python code that runs on Java Virtual Machine (JVM) ✅ Useful when you want to integrate with Java code or use Java libraries	🔹 Written in Java language 🔹 Allows Python scripts to interact with Java classes, GUIs, frameworks 🔹 Works well in Java-based enterprise environments	📌 Java GUI using Python: python<br>from java.awt import Frame<br>f = Frame("Hello Jython")<br>f.setVisible(True)
PyPy (Python Python – Just-in-Time Compiler)	✅ Best for CPU-heavy and performance-critical applications like games, simulations, web scraping	🔹 Uses JIT (Just-In-Time) compiler to run Python code much faster 🔹 No code change needed — just use PyPy instead of Python 🔹 Compatible with most Python 3 code	📌 Run script with PyPy: pypy myscript.py 📌 Used for: speed optimization without code rewriting
MicroPython (Microcontroller Python)	✅ Used in embedded systems, IoT (Internet of Things), hardware-level programming ✅ Runs on tiny devices like sensors, boards, microcontrollers	🔹 Lightweight Python interpreter (very small memory footprint) 🔹 Works on microchips like ESP32, Raspberry Pi Pico, Arduino 🔹 Designed for real-time low-power devices	📌 Control LED on ESP32: python<br>from machine import Pin<br>led = Pin(2, Pin.OUT)<br>led.value(1) 📌 Used in: Smart home gadgets, Wearables, Sensors

✅ What Makes a Language? – Easy Table

Element	Meaning (Simple)	Examples
Alphabet	Basic letters or symbols used to form words	🔤 English: A–Z 🔢 Programming: A–Z, 0–9, +, -, *, /, () etc.
Lexis (Words)	Valid words from the language's dictionary	✅ computer is a word ❌ cmoptrue is not ✅ Python: print, if
Syntax	Rules for writing correct sentence structure	✅ print("Hello") ❌ print "Hello" (Wrong in Python 3)
Semantics	Logical meaning of a sentence	✅ "I ate a doughnut" ❌ "A doughnut ate me" (Funny but illogical)

🧠 Code Levels Explained (with Example)

Level	Code Example	Who Understands It	Description
High-Level Code	print("Hello") (Python)	👩‍💻 Humans (Programmers)	Easy to read/write. Used in Python, Java, C, etc.
Assembly Code	MOV AL, 61h	🧑‍🔧 Assembly Programmers	Low-level readable commands close to machine code.
Machine Code	10110000 01100001	🧠 CPU (Processor)	Binary (0s and 1s) — directly executed by the computer hardware.

Module 1 Sabhi Vikalp Question

Question	Answer	Explanation	Example
What do you call a command-line interpreter which lets you interact with your OS and execute Python commands and scripts?	A console	A console (or command line) is where you type text commands to run programs. You use it to run Python code or tell your computer what to do.	Open Command Prompt or Terminal, and type python myscript.py to run a Python script.
What is CPython?	It's the default, reference implementation of Python, written in the C language	CPython is the most common version of Python, and it is written in the C programming language. It's the version you usually install from Python's official website.	When you download Python from python.org, you are using CPython.
What is the expected behavior of the following program? print("Hello!")	The program will output Hello! to the screen	The print function will show the text Hello! on the screen. The quotes around Hello! are only for the code, not shown in the output.	Output: Hello!
What do you call a file containing a program written in a high-level programming language?	A source file	A source file is where the code of a program is written in a language like Python. It ends with .py in Python.	Example: my_program.py is a Python source file.
What is true about compilation? (Select two answers)	The code is converted directly into machine code executable by the processor It tends to be faster than interpretation	Compilation turns your code into machine language (that the computer can understand directly). This is faster to run, but you need to recompile every time you change your code.	Example: If you compile a C program with gcc, you get an executable .exe file that you can run directly.
What is a script?	It's a text file that contains instructions which make up a Python program	A script is a Python program written in a file that you can run to make the computer do something.	Example: A script could be my_script.py that prints Hello, world! when run.
What is the best definition of a high-level programming language?	It's a language that allows you to write instructions in a human-readable way	High-level languages are easy for humans to understand, like Python, because you don't need to know how the computer works inside.	Example: In Python, you can write print("Hello"), which is easy to read, compared to machine code.
What is machine code?	It's the lowest-level code that is directly executed by the CPU	Machine code is the binary code (ones and zeros) that the computer's processor understands. It is the most basic form of code.	Example: 10110000 01100001 is machine code that the CPU understands directly.
What is true about interpretation? (Select two answers)	The source code is translated line by line You don’t need a separate file to distribute	Interpretation means running the code line by line, instead of compiling it into a separate file. This makes it slower but easy to test and run directly.	Example: If you run python myscript.py, Python reads and executes the code line by line.
What is the expected behavior of the following program? x = 5 + 3 print(x)	The program will output 8 to the screen	The program adds 5 + 3 and stores it in x. Then, it prints the value of x, which is 8.	Output: 8