Python Introduction and Basic Syntax Overview

Introduction

Python is a high‑level, interpreted, interactive, object‑oriented scripting language created by Guido van Rossum in 1989; the first public release appeared in 1991.

Key Features

Easy to learn with simple syntax and few keywords.

Readable code and maintainable source.

Extensive standard library that works across Unix, Windows and macOS.

Interactive mode, portable, extensible via C/C++, database interfaces, GUI support, embedding, and strong OOP.

Basic Syntax

Running Python

Enter the interactive interpreter with python and exit using exit() or Ctrl + D. Execute a script file with python script-file.py. A shebang line #!/usr/bin/env python allows direct execution of /path/to/script-file.py (Unix only).

Encoding

Source files are UTF‑8 by default. Explicit encoding can be declared as the first line, e.g. # -*- coding: utf-8 -*- or # encoding: utf-8.

Identifiers

Identifiers must start with a letter or underscore ( _) and may contain letters, digits, and underscores; they are case‑sensitive. Non‑ASCII identifiers are allowed from Python 3.x but discouraged.

Keywords

Keywords cannot be used as identifiers. The keyword module lists them, for example:

import keyword
keyword.kwlist

which outputs ['False','None','True','and',...].

Operators

Python supports arithmetic, comparison, assignment, bitwise, logical, membership, and identity operators and follows standard precedence rules (parentheses can override).

Variables

Variables must be assigned before use; attempting to read an undefined name raises NameError.

Data Types

Core types include bool (True/False), int , float , complex , str , and bytes . Numeric operations follow Python’s rules (e.g., / always returns float, // performs floor division). Strings are immutable, support concatenation ( +) and repetition ( *), and can be defined with single, double, or triple quotes. Bytes are prefixed with b and require explicit encoding/decoding.

Input and Output

Use input() to read user input and print() for output; print(..., end="") suppresses the newline.

Import Statements

Modules can be imported with import module_name or specific objects with from module_name import name, and all symbols with from module_name import *.