Python
Defining and Calling Functions
A function packages a piece of work behind a name. def creates it, the call runs it, and return decides what comes back - which is None if you never s...
Python
A complete core Python path: syntax, data types, operators, strings, control flow, collections, functions, exceptions, files, modules, the standard library, OOP, iterators, generators, decorators, internals, concurrency, regular expressions, testing, typing, performance, security, problem solving, projects, interview preparation and exams.
110 notes in 33 topics
Topics in Python
Basics 5
Data Types 4
Operators 5
Strings 5
Control Flow 5
Lists 3
Tuples 2
Sets 2
Dictionaries 3
Comprehensions 2
Functions 4
Advanced Functions 2
Recursion 2
Exception Handling 4
File Handling 4
Modules 3
Standard Library 6
OOP 5
Advanced OOP 5
Iterators and Generators 3
Decorators 2
Context Managers 1
Descriptors and Dataclasses 2
Python Internals 4
Concurrency 4
Regular Expressions 3
Serialization 2
Command Line Python 2
Testing and Debugging 3
Type Hints 2
Performance 3
Python Security 2
DSA with Python 6
Notes
Python
Function Arguments: Defaults, *args and **kwargs
Positional, keyword, default, variable length and keyword only arguments - five styles, one fixed order, and one famous trap involving mutable default...
Python
Scope and the LEGB Rule
Python resolves a name by looking in four places in a fixed order: local, enclosing, global, built-in. Assignment anywhere in a function makes the nam...
Python
Lambda Functions
A lambda is a small anonymous function written as a single expression. It exists for the places where naming a function would add nothing.
Python
First-Class and Higher-Order Functions
Functions in Python are ordinary objects. They can be stored, passed, returned and built at runtime, and that fact underlies sorting keys, decorators...
Python
Nested Functions and Closures
A closure is an inner function that keeps hold of variables from the function that created it, long after that function has returned.
Python
Recursion: How It Works
A recursive function calls itself on a smaller version of the problem until it reaches a case it can answer directly. Every one needs a base case and...
Python
Recursive Problems and Their Limits
Fibonacci shows why naive recursion can be catastrophically slow, memoisation fixes it in one line, and some problems are worth the stack frames while...
Python
Errors in Python: Syntax, Runtime and Logical
Three kinds of error, found at three different moments. Only one of them can be caught, and the one that catches nobody out is the most dangerous.
Python
try, except, else and finally
try runs risky code, except handles a failure, else runs when nothing failed, and finally always runs. Each block has one job and using the wrong one...
Python
The Exception Hierarchy
Every exception is a class in one inheritance tree. Catching a parent catches all its children, which is what makes handler order and handler width ma...
Python
raise and Custom Exceptions
raise signals a failure your own code has detected. A custom exception class gives that failure a name callers can catch precisely.