Overview

To master Python, knowing its built-in functions is like having a toolbox where you understand every tool — when and how to use it. Python has 70+ built-in functions, but here are the most important and frequently used ones every serious Python programmer should know well.

🧠 Core Built-ins You Must Master

🔍 Inspecting & Debugging

type() – Get the type of a value.
id() – Unique ID of an object (useful for identity checks).
dir() – See what’s inside an object.
help() – Get documentation on an object or function.
vars() – See __dict__ (attributes) of an object.

🔄 Type Conversion & Casting

int(), float(), str(), bool() – Convert between data types.
list(), set(), tuple(), dict() – Create or convert between containers.
ord() / chr() – Character-code conversions.
bin(), hex(), oct() – Convert integers to binary/hex/oct strings.

🔁 Loops and Iterables

range() – Create number ranges for loops.
enumerate() – Loop with index and value.
zip() – Combine multiple iterables element-wise.
map() – Apply a function to all items in an iterable.
filter() – Filter items using a condition.
reversed() – Reverse an iterable.
sorted() – Sort anything.
len() – Length of an object.

🧮 Math & Numbers

sum() – Sum of a list of numbers.
min() / max() – Find smallest/largest.
abs() – Absolute value.
round() – Round a number.
pow() – Power (can also use **).

📦 Containers & Collections

all() – True if all elements are true.
any() – True if at least one is true.
isinstance() – Check if something is of a certain type.
slice() – Create slice objects (used for indexing).

🔧 Functional Programming

lambda – Create anonymous functions.
callable() – Check if an object can be called like a function.
eval() – Evaluate a string as Python code (careful!).
exec() – Execute dynamically created Python code (dangerous!).

🗃️ Object Handling

getattr(), setattr(), hasattr(), delattr() – Dynamic attribute access.
staticmethod(), classmethod() – Used in classes.
property() – Define managed attributes in classes.

⛏️ I/O (Input/Output)

print() – Output to console.
input() – Get user input.

🧱 Structure and Flow

compile() – Turn source code into code objects.
globals() / locals() – Access global/local symbol tables.
__import__() – Dynamic import of a module.

🧰 Optional but Useful

next() – Get next item from an iterator.
iter() – Turn something into an iterator.
memoryview() – Access byte-level data efficiently.
format() – String formatting.

✅ What You Should Do

Read the docs: Python Built-in Functions
Practice in real code: Use them in small projects or exercises.
Explore via dir(__builtins__): Try this in Python to see them all.

Would you like a cheat sheet or practice problems to go with these?