Python Builtin Functions: A Concise Reference

Python builtin functions

Python Built-ins Functions: A Complete Guide

Python is renowned for its simplicity, readability, and power: qualities that stem in large part from its rich set of built-in functions, values, and exceptions. These python builtin functions are preloaded into Python’s core, providing developers with ready-to-use tools for performing common tasks without needing to import external modules.

From data inspection and type conversion to iteration, mathematical operations, and error handling, Python’s built-in features empower developers to write clean, concise, and efficient code. Whether you are building simple scripts or complex applications, understanding these built-ins is essential to mastering the language.

In this guide, we provide a comprehensive reference to all 100 Python built-ins, each presented with:

  • Definition and usage — a clear explanation of what the function or exception does.
  • Syntax — the precise way to use it.
  • Parameter values — the meaning of its arguments.
  • Examples — practical code snippets to demonstrate its usage.

This resource is designed as both a learning tool for Python beginners and a quick reference for experienced developers — a single, comprehensive guide to help you leverage the full power of Python’s built-in capabilities.

By mastering these built-ins, you not only improve your programming efficiency but also elevate the quality and maintainability of your code.

Python Builtin Functions abs: absolute value of a number

Definition and Usage of abs

Returns the absolute value of a number.

Syntax of abs

abs(x)

Parameter Values of abs

x: A number (integer, float, or complex).

Example of abs

Python
print(abs(-5.2)) # Output: 5.2 
print(abs(3 + 4j)) # Output: 5.0
Python

Python Builtin Functions aiter: asynchronous iterator adapter

Definition and Usage of aiter

Returns an asynchronous iterator for an asynchronous iterable.

Syntax of aiter

aiter(async_iterable)

Parameter Values of aiter

async_iterable: An object that supports the asynchronous iteration protocol.

Example of aiter

Python
# An example using a simple async iterable
import nest_asyncio
nest_asyncio.apply()

async def my_async_gen():
    yield 1
    yield 2

async def main():
    async_iter = aiter(my_async_gen())
    print(await anext(async_iter)) # 1
    print(await anext(async_iter)) # 2

import asyncio
asyncio.run(main())
Python

all: True if every element is truthy

Definition and Usage of Python builtin all

Returns True if all elements of an iterable are truthy (or if the iterable is empty), otherwise returns False.

Syntax of Python builtin all

all(iterable)

Parameter Values of Python builtin all

iterable: An iterable object (list, tuple, etc.).

Example of Python builtin all

Python
print(all([True, 1, 'hello'])) # Output: True 
print(all([True, 0, 'hello'])) # Output: False
Python

any: True if any element is truthy

Definition and Usage of Python builtin any

Returns True if any element of an iterable is truthy, otherwise returns False.

Syntax of Python builtin any

any(iterable)

Parameter Values of Python builtin any

iterable: An iterable object.

Example of Python builtin any

Python builtin any
print(any([0, '', False, 5])) # Output: True 
print(any([0, '', False])) # Output: False
Python builtin any

anext: get next item from async iterator

Definition and Usage of Python builtin iterator

Returns the next item from an asynchronous iterator.

Syntax of Python builtin iterator

anext(async_iterator[, default])

Parameter Values of Python builtin iterator

async_iterator: An asynchronous iterator.

default: Optional value to return if the iterator is exhausted.

Example of Python builtin iterator

Python builtin iterator
import nest_asyncio
nest_asyncio.apply()
async def gen():
    yield 'a' 
    yield 'b' 
async def main():
    it = gen() 
    print(await anext(it)) # a 
    print(await anext(it, 'c')) # b 
    print(await anext(it, 'c')) # c 

import asyncio 
asyncio.run(main())
Python builtin iterator

ascii — ASCII-only representation of an object

Definition and Usage of Python builtin ascii

Returns a string containing a printable representation of an object, escaping non-ASCII characters.

Syntax of Python builtin ascii

ascii(object)

Parameter Values of Python builtin ascii

object: Any Python object.

Example of Python builtin ascii

print(ascii(‘Hello, 世界’)) # Output: ‘Hello, \\u4e16\\u754c’

bin: binary string of an int

Definition and Usage of Python builtin bin

Converts an integer to a binary string prefixed with “0b”.

Syntax of Python builtin bin

bin(x)

Parameter Values of Python builtin bin

x: An integer.

Example of Python builtin bin

print(bin(10)) # Output: 0b1010

breakpoint: drop into debugger (calls sys.breakpointhook)

Definition and Usage of Python builtin breakpoint

Drops the program into the debugger at the point of the call.

Syntax of Python builtin breakpoint

breakpoint(*args, **kwargs)

Parameter Values of Python builtin breakpoint

Optional arguments passed to sys.breakpointhook.

Example of Python builtin breakpoint

Python
def my_function():
    x = 5 
    breakpoint() 
    y = 10 # Running this will pause execution on line 3 and open a debugger prompt.
Python

bool: convert to boolean

Definition and Usage of Python builtin bool

Converts a value to a boolean, True or False.

Syntax of Python builtin bool

bool(x)

Parameter Values of Python builtin bool

x: Any object.

Example of Python builtin bool

Python
print(bool(1)) # Output: True 
print(bool([])) # Output: False 
print(bool('hello')) # Output: True
Python

bytearray: mutable sequence of bytes

Definition and Usage of Python builtin bytes

Returns a new array of bytes. It is a mutable sequence.

Syntax of Python builtin bytes

bytearray([source[, encoding[, errors]]])

Parameter Values of Python builtin bytes

source: Optional. An iterable of integers, a string, or an integer.

Example of Python builtin bytes

Python
b = bytearray(b'hello') 
b[0] = 72 
print(b) # Output: bytearray(b'Hello')
Python

bytes: immutable bytes sequence

Definition and Usage of Python builtin sequence

Returns a new immutable sequence of bytes.

Syntax of Python builtin sequence

bytes([source[, encoding[, errors]]])

Parameter Values of Python builtin sequence

source: Optional. Similar to bytearray.

Example of Python builtin sequence

Python
b = bytes([72, 101, 108, 108, 111]) 
print(b) # Output: b'Hello'
Python

callable: check if object is callable

Definition and Usage of Python builtin callable

Returns True if the object appears to be callable, False otherwise.

Syntax of Python builtin callable

callable(object)

Parameter Values of Python builtin callable

object: Any object.

Example of Python builtin callable

Python
def my_func():
    pass 
    print(callable(my_func)) # Output: True 
    print(callable(5)) # Output: False

my_func()
Python

chr: character from Unicode code point

Definition and Usage of Python builtin chr

Returns the character corresponding to an integer Unicode code point.

Syntax of Python builtin chr

chr(i)

Parameter Values of Python builtin chr

i: An integer representing a Unicode code point.

Example of Python builtin chr

Python
print(chr(65)) # Output: 'A' 
print(chr(97)) # Output: 'a' 
print(chr(8364)) # Output: '€'
Python

classmethod: define a class method decorator

Definition and Usage of Python builtin classmethod

A decorator that transforms a method into a class method. The first argument of a class method is the class itself.

Syntax of Python builtin classmethod

@classmethod

Parameter Values of Python builtin classmethod

None, used as a decorator.

Example of Python builtin classmethod

Python
class MyClass: 
    @classmethod
    def my_method(cls):
        return cls.__name__ 
print(MyClass.my_method()) # Output: MyClass
Python

compile: compile source to code object

Definition and Usage of Python builtin compile

Compiles a string of Python code into a code object that can be executed later using exec() or eval().

Syntax of Python builtin compile

compile(source, filename, mode[, flags[, dont_inherit]])

Parameter Values of Python builtin compile

source: The source code string. filename: A string for the filename. mode: exec, eval, or single.

Example of Python builtin compile

Python
code = compile('x = 5\nprint(x)', '<string>', 'exec') 
exec(code) # Output: 5
Python

complex: complex number constructor

Definition and Usage

Creates a complex number or converts a string to a complex number.

Syntax

complex([real[, imag]])

Parameter Values

real: The real part. imag: The imaginary part.

Example

Python
c1 = complex(2, 5) # 2 + 5j 
c2 = complex('1+2j') 
print(c1) # (2+5j) 
print(c2) # (1+2j)
Python

delattr: delete an attribute from an object

Definition and Usage

Deletes a named attribute from an object. delattr(obj, ‘name’) is equivalent to del obj.name.

Syntax

delattr(object, name)

Parameter Values

object: The object. name: A string with the attribute’s name.

Example

Python
class MyClass:
    x = 5 
obj = MyClass() 
print(obj.x) #5
delattr(obj, 'x') 
print(obj.x) # This would raise an AttributeError
Python

dict: dictionary constructor / type

Definition and Usage

Creates a new dictionary object.

Syntax

dict(**kwargs) or dict(mapping) or dict(iterable)

Parameter Values

Can take keyword arguments, a dictionary, or an iterable of key-value pairs.

Example

Python
d = dict(a=1, b=2) 
print(d) # Output: {'a': 1, 'b': 2}
Python

dir: list attributes of an object

Definition and Usage

Returns a list of names in the current local scope, or a list of attributes of an object.

Syntax

dir([object])

Parameter Values

object: Optional. An object.

Example

Python
print(dir([])) # Output: A list of list methods like 'append', 'clear', etc. 
print(dir()) # Output: A list of names in the current scope
Python

divmod: quotient and remainder pair

Definition and Usage

Returns a pair of numbers, the quotient and the remainder, from integer division.

Syntax

divmod(a, b)

Parameter Values

a: The numerator. b: The denominator.

Example

Python
print(divmod(10, 3)) # Output: (3, 1)
Python

enumerate: iterator of (index, value) pairs

Definition and Usage

Returns an enumerate object, which is an iterator that yields pairs of (index, value) for an iterable.

Syntax

enumerate(iterable, start=0)

Parameter Values

iterable: An iterable.

start: Optional, the starting index.

Example

Python
l = ['a', 'b', 'c'] 
for i, item in enumerate(l):
    print(f"{i}: {item}") # Output: # 0: a # 1: b # 2: c
Python

eval — evaluate an expression (use carefully)

Definition and Usage

Parses and evaluates a Python expression from a string.

Syntax

eval(expression[, globals[, locals]])

Parameter Values

expression: A string. globals, locals: Dictionaries for the global and local scope.

Example

Python
print(eval('3 + 5')) # Output: 8
Python

exec: execute dynamically created code

Definition and Usage

Executes a string of Python statements.

Syntax

exec(object[, globals[, locals]])

Parameter Values

object: A string or code object. globals, locals: Dictionaries.

Example

Python
exec('x = 10\nprint(x)') # Output: 10
Python

filter: filter values by predicate (iterator)

Definition and Usage

Constructs an iterator from elements of an iterable for which a function returns true.

Syntax

filter(function, iterable)

Parameter Values

function: A function that returns a boolean.

iterable: An iterable.

Example

Python
def is_even(n): 
    return n % 2 == 0
    
numbers = [1, 2, 3, 4, 5] 
even_numbers = list(filter(is_even, numbers)) 
print(even_numbers) # Output: [2, 4]
Python

float: float constructor

Definition and Usage

Converts an object to a floating-point number.

Syntax

float([x])

Parameter Values

x: A number or string.

Example

Python
print(float('3.14')) # Output: 3.14
Python

format — format value with spec

Definition and Usage of spec

Formats a value using a format specifier.

Syntax of spec

format(value[, format_spec])

Parameter Values of spec

value: The value to format.

format_spec: A string specifying the format.

Example of spec

Python
print(format(100, '0x')) # Output: 64
Python

frozenset — immutable set type

Definition and Usage of frozenset

Creates an immutable set object. Elements cannot be added or removed.

Syntax of frozenset

frozenset([iterable])

Parameter Values of frozenset

iterable: Optional.

Example of frozenset

Python
fs = frozenset([1, 2, 3])
fs.add(4) # This would raise an AttributeError
Python

Python Builtin Functions getattr: get attribute with optional default

Definition and Usage of Python builtin function getattr

Returns the value of a named attribute of an object.

Syntax of Python builtin function getattr

getattr(object, name[, default])

Parameter Values of Python builtin function getattr

  • object: The object.
  • name: A string representing the attribute name.
  • default: Optional default value returned if attribute does not exist.

Example of Python builtin function getattr

Python
class MyClass:
    x = 5

obj = MyClass()
print(getattr(obj, 'x'))      # Output: 5
print(getattr(obj, 'y', 10))  # Output: 10
Python

Python Builtin Functions globals: dictionary of global symbols

Definition and Usage of Python builtin function globals

Returns a dictionary representing the current global symbol table.

Syntax of Python builtin function globals

globals()

Parameter Values of Python builtin function globals

  • None

Example of Python builtin function globals

Python
x = 10
g = globals()
print(g['x'])  # Output: 10
Python

Python Builtin Functions hasattr: test for attribute existence

Definition and Usage of Python builtin function hasattr

Returns True if the object has the given named attribute, False otherwise.

Syntax of Python builtin function hasattr

hasattr(object, name)

Parameter Values of Python builtin function hasattr

  • object: The object.
  • name: The attribute name as a string.

Example of Python builtin function hasattr

Python
class MyClass:
    x = 5

obj = MyClass()
print(hasattr(obj, 'x'))  # Output: True
print(hasattr(obj, 'y'))  # Output: False
Python

Python Builtin Functions hash: hash value for hashable object

Definition and Usage of Python builtin function hash

Returns the hash value of an object, if it has one.

Syntax of Python builtin function hash

Python
hash(object)
Python

Parameter Values of Python builtin function hash

  • object: A hashable object (string, number, etc.).

Example of Python builtin function hash

Python
print(hash('hello'))
print(hash(5))
Python

Python Builtin Functions help: interactive help (or doc lookup)

Definition and Usage of Python builtin function help

Invokes the built-in help system.

Syntax of Python builtin function help

help([object])

Parameter Values of Python builtin function help

  • object: Optional.

Example of Python builtin function help

Python
help(str)   # Provides documentation for the str type
Python

Python Builtin Functions hex: hexadecimal string of an int

Definition and Usage of Python builtin function hex

Converts an integer to a hexadecimal string prefixed with “0x”.

Syntax of Python builtin function hex

hex(x)

Parameter Values of Python builtin function hex

  • x: An integer.

Example of Python builtin function hex

Python
print(hex(255))  # Output: 0xff
Python

Python Builtin Functions id: unique identifier (object identity)

Definition and Usage of Python builtin function id

Returns the “identity” of an object. This is an integer guaranteed to be unique and constant for the lifetime of the object.

Syntax of Python builtin function id

id(object)

Parameter Values of Python builtin function id

  • object: Any object.

Example of Python builtin function id

Python
x = [1, 2]
print(id(x))
Python

Python Builtin Functions input: read a line from stdin

Definition and Usage of Python builtin function input

Reads a line from standard input, converts it to a string, and returns it.

Syntax of Python builtin function input

input([prompt])

Parameter Values of Python builtin function input

  • prompt: Optional. A string to display before reading input.

Example of Python builtin function input

Python
name = input("Enter your name: ")
print(f"Hello, {name}!")
Python

Python Builtin Functions int: integer constructor

Definition and Usage of Python builtin function int

Converts a number or string to an integer.

Syntax of Python builtin function int

int([x[, base]])

Parameter Values of Python builtin function int

  • x: A number or string.
  • base: Optional, the base of the number string.

Example of Python builtin function int

Python
print(int('10', 2))  # Output: 2
Python

Python Builtin Functions isinstance: type-check instance against type(s)

Definition and Usage of Python builtin function isinstance

Returns True if the object is an instance of the class or of a subclass thereof.

Syntax of Python builtin function isinstance

isinstance(object, classinfo)

Parameter Values of Python builtin function isinstance

  • object: The object.
  • classinfo: A class, tuple of classes, or union type.

Example of Python builtin function isinstance

Python
print(isinstance(5, int))       # Output: True
print(isinstance('hello', str)) # Output: True
Python

Python Builtin Functions issubclass: check subclass relationship

Definition and Usage of Python builtin function issubclass

Returns True if class is a subclass of classinfo.

Syntax of Python builtin function issubclass

issubclass(class, classinfo)

Parameter Values of Python builtin function issubclass

  • class: A class.
  • classinfo: A class or tuple of classes.

Example of Python builtin function issubclass

Python
class Parent: pass
class Child(Parent): pass
print(issubclass(Child, Parent))  # Output: True
Python

Python Builtin Functions iter: get iterator from iterable

Definition and Usage of Python builtin function iter

Returns an iterator object for an iterable.

Syntax of Python builtin function iter

iter(object[, sentinel])

Parameter Values of Python builtin function iter

  • object: An iterable.
  • sentinel: Optional, used for function-based iterators.

Example of Python builtin function iter

Python
it = iter([1, 2, 3])<br>print(next(it))  # Output: 1
Python

Python Builtin Functions len: length of a container

Definition and Usage of Python builtin function len

Returns the number of items in a container (sequence, mapping, etc.).

Syntax of Python builtin function len

len(s)

Parameter Values of Python builtin function len

  • s: A container object.

Example of Python builtin function len

Python
print(len("hello"))  # Output: 5
Python

Python Builtin Functions list: list constructor / type

Definition and Usage of Python builtin function list

Creates a new list.

Syntax of Python builtin function list

list([iterable])

Parameter Values of Python builtin function list

  • iterable: Optional.

Example of Python builtin function list

Python
print(list('abc'))  # Output: ['a', 'b', 'c']
Python

Python Builtin Functions locals: dictionary of local symbols

Definition and Usage of Python builtin function locals

Returns a dictionary representing the current local symbol table.

Syntax of Python builtin function locals

locals()

Parameter Values of Python builtin function locals

  • None

Example of Python builtin function locals

Python
def my_func():
    x = 5
    print(locals()['x'])
my_func()  # Output: 5
Python

Python Builtin Functions map: apply function to each item (iterator)

Definition and Usage of Python builtin function map

Applies a function to every item of an iterable and returns a new iterator.

Syntax of Python builtin function map

map(function, iterable, …)

Parameter Values of Python builtin function map

  • function: A function.
  • iterable: One or more iterables.

Example of Python builtin function map

Python
def square(x):
    return x * x

numbers = [1, 2, 3]
squared = list(map(square, numbers))
print(squared)  # Output: [1, 4, 9]
Python

Python Builtin Functions max: maximum value (with key support)

Definition and Usage of Python builtin function max

Returns the largest item in an iterable or the largest of two or more arguments.

Syntax of Python builtin function max

max(iterable, *[, key, default])
max(arg1, arg2, *args[, key])

Parameter Values of Python builtin function max

  • iterable or arguments.
  • key: Optional function to customize comparison.
  • default: Optional value returned if iterable is empty.

Example of Python builtin function max

Python
print(max([1, 5, 2]))           # Output: 5
print(max('apple', 'banana'))   # Output: banana
Python

Python Builtin Functions memoryview: memory view of binary object

Definition and Usage of Python builtin function memoryview

Returns a memory view object from a given argument, allowing access to an object’s internal buffer without copying.

Syntax of Python builtin function memoryview

memoryview(obj)

Parameter Values of Python builtin function memoryview

  • obj: A bytes-like object.

Example of Python builtin function memoryview

Python
b = b'hello'
mv = memoryview(b)
print(mv[0])  # Output: 104
Python

Python Builtin Functions min: minimum value (with key support)

Definition and Usage of Python builtin function min

Returns the smallest item in an iterable or the smallest of two or more arguments.

Syntax of Python builtin function min

min(iterable, *[, key, default])
min(arg1, arg2, *args[, key])

Parameter Values of Python builtin function min

  • iterable or arguments.
  • key: Optional function to customize comparison.
  • default: Optional value returned if iterable is empty.

Example of Python builtin function min

Python
print(min([1, 5, 2]))  # Output: 1
Python

Python Builtin Functions next: advance iterator, optional default

Definition and Usage of Python builtin function next

Retrieves the next item from an iterator.

Syntax of Python builtin function next

next(iterator[, default])

Parameter Values of Python builtin function next

  • iterator: An iterator.
  • default: Optional value to return if iterator is exhausted.

Example of Python builtin function next

Python
it = iter([1, 2])
print(next(it))  # Output: 1
print(next(it))  # Output: 2
Python

Python Builtin Functions object: base object type

Definition and Usage of Python builtin function object

The base class for all new-style classes.

Syntax of Python builtin function object

object()

Parameter Values of Python builtin function object

  • None.

Example of Python builtin function object

Python
class MyClass(object):
    pass

print(issubclass(MyClass, object))  # Output: True
Python

Python Builtin Functions oct: octal string of an int

Definition and Usage of Python builtin function oct

Converts an integer to an octal string prefixed with “0o”.

Syntax of Python builtin function oct

oct(x)

Parameter Values of Python builtin function oct

  • x: An integer.

Example of Python builtin function oct

Python
print(oct(8))  # Output: 0o10
Python

Python Builtin Functions open: open a file and return a file object

Definition and Usage of Python builtin function open

Opens a file and returns a corresponding file object.

Syntax of Python builtin function open

open(file, mode=’r’, …)

Parameter Values of Python builtin function open

  • file: The path to the file.
  • mode: The file open mode.

Example of Python builtin function open

Python
with open('my_file.txt', 'w') as f:
    f.write('Hello, world!')
Python

Python Builtin Functions ord: integer code point of a single character

Definition and Usage of Python builtin function ord

Returns an integer representing the Unicode code point of a character.

Syntax of Python builtin function ord

ord(c)

Parameter Values of Python builtin function ord

  • c: A single character string.

Example of Python builtin function ord

Python
print(ord('A'))    # Output: 65
print(ord('€'))    # Output: 8364
Python

Python Builtin Functions pow: power, optional modulo

Definition and Usage of Python builtin function pow

Returns x to the power of y. If z is given, returns x**y % z.

Syntax of Python builtin function pow

Parameter Values of Python builtin function pow

  • x, y: Numbers.
  • z: Optional number for modulo.

Example of Python builtin function pow

Python
print(pow(2, 3))       # Output: 8
print(pow(2, 3, 5))    # Output: 3
Python

Python Builtin Functions print: print objects to stream

Definition and Usage of Python builtin function print

Prints objects to the text stream file, separated by sep and followed by end.

Syntax of Python builtin function print

Parameter Values of Python builtin function print

  • objects: The objects to print.
  • sep: Separator between objects (default is space ‘ ‘).
  • end: String appended after the last object (default is newline ‘\n’).
  • file: Output stream (default is sys.stdout).
  • flush: Boolean specifying whether to forcibly flush the stream.

Example of Python builtin function print

Python
print('hello', 'world', sep='-')  # Output: hello-world
Python

Python Builtin Functions property: create property attribute

Definition and Usage of Python builtin function property

Returns a property attribute used to manage class attributes via methods.

Syntax of Python builtin function property

Parameter Values of Python builtin function property

  • fget: Function for getting the attribute value.
  • fset: Function for setting the attribute value.
  • fdel: Function for deleting the attribute value.
  • doc: Optional docstring.

Example of Python builtin function property

Python
class MyClass:
    def __init__(self, x):
        self._x = x

    @property
    def x(self):
        return self._x

obj = MyClass(5)
print(obj.x)  # Output: 5
Python

Python Builtin Functions range: sequence of integers (efficient)

Definition and Usage of Python builtin function range

Returns an immutable sequence object that generates a series of integers.

Syntax of Python builtin function range

Parameter Values of Python builtin function range

  • start: Starting integer (optional).
  • stop: Stop integer (exclusive).
  • step: Increment between integers (optional).

Example of Python builtin function range

Python
for i in range(3):
    print(i)  # Outputs: 0, 1, 2
Python

Python Builtin Functions repr: developer-friendly string repr

Definition and Usage of Python builtin function repr

Returns a string containing a printable representation of an object, usually valid Python code.

Syntax of Python builtin function repr

Parameter Values of Python builtin function repr

  • object: Any object.

Example of Python builtin function repr

Python
print(repr('hello'))  # Output: 'hello'
Python

Python Builtin Functions reversed: reverse iterator over a sequence

Definition and Usage of Python builtin function reversed

Returns a reverse iterator over a sequence.

Syntax of Python builtin function reversed

Parameter Values of Python builtin function reversed

  • seq: A sequence object that supports reversal.

Example of Python builtin function reversed

Python
l = [1, 2, 3]<br>print(list(reversed(l)))  # Output: [3, 2, 1]
Python

Python Builtin Functions round: round a number to given digits

Definition and Usage of Python builtin function round

Rounds a number to a specified number of decimal places.

Syntax of Python builtin function round

Parameter Values of Python builtin function round

  • number: A number.
  • ndigits: Optional number of decimal places.

Example of Python builtin function round

Python
print(round(3.14159, 2))  # Output: 3.14
Python

Python Builtin Functions set: mutable set type

Definition and Usage of Python builtin function set

Creates a new set object.

Syntax of Python builtin function set

Parameter Values of Python builtin function set

  • iterable: Optional iterable to initialize the set.

Example of Python builtin function set

Python
s = {1, 2, 3, 3}
print(s)  # Output: {1, 2, 3}
s.add(4)
print(s)  # Output: {1, 2, 3, 4}
Python

Python Builtin Functions setattr: set attribute on an object

Definition and Usage of Python builtin function setattr

Sets the value of a named attribute on an object. Equivalent to obj.name = value.

Syntax of Python builtin function setattr

Parameter Values of Python builtin function setattr

  • object: The object.
  • name: The attribute name as a string.
  • value: The new value.

Example of Python builtin function setattr

Python
class MyClass: pass
obj = MyClass()
setattr(obj, 'x', 5)
print(obj.x)  # Output: 5
Python

Python Builtin Functions slice: create a slice object

Definition and Usage of Python builtin function slice

Returns a slice object that can be used for slicing sequences.

Syntax of Python builtin function slice

Parameter Values of Python builtin function slice

  • start: Starting index (optional).
  • stop: Ending index.
  • step: Step value (optional).

Example of Python builtin function slice

Python Builtin Functions sorted: return a new sorted list

Definition and Usage of Python builtin function sorted

Returns a new sorted list from the items in an iterable.

Syntax of Python builtin function sorted

Parameter Values of Python builtin function sorted

  • iterable: An iterable.
  • key: Optional function to extract a comparison key.
  • reverse: True for descending order (default False).

Example of Python builtin function sorted

Python
l = [3, 1, 2]
print(sorted(l))  # Output: [1, 2, 3]
Python

Python Builtin Functions staticmethod: define a static method decorator

Definition and Usage of Python builtin function staticmethod

A decorator that transforms a method into a static method. It doesn’t receive an implicit first argument.

Syntax of Python builtin function staticmethod

Parameter Values of Python builtin function staticmethod

  • None (used as a decorator).

Example of Python builtin function staticmethod

Python
class MyClass:
    @staticmethod
    def add(x, y):
        return x + y
print(MyClass.add(2, 3))  # Output: 5
Python

Python Builtin Functions str: string constructor / type

Definition and Usage of Python builtin function str

Creates a new string object.

Syntax of Python builtin function str

Parameter Values of Python builtin function str

  • object: An object to convert.
  • encoding: Encoding type (optional).
  • errors: How to handle encoding errors (optional).

Example of Python builtin function str

Python Builtin Functions sum: sum of items (with start)

Definition and Usage of Python builtin function sum

Sums the items of an iterable.

Syntax of Python builtin function sum

Parameter Values of Python builtin function sum

  • iterable: An iterable of numbers.
  • start: Optional value to add to the sum.

Example of Python builtin function sum

Python
print(sum([1, 2, 3]))        # Output: 6
print(sum([1, 2, 3], 10))    # Output: 16
Python

Python Builtin Functions super: proxy for parent class methods

Definition and Usage of Python builtin function super

Returns a proxy object that delegates method calls to a parent or sibling class.

Syntax of Python builtin function super

Parameter Values of Python builtin function super

  • type, object_or_type: Optional for specifying the class hierarchy.

Example of Python builtin function super

Python
class Parent:
    def greeting(self):
        return 'Hello from Parent'

class Child(Parent):
    def greeting(self):
        return super().greeting() + ' and Child'

c = Child()
print(c.greeting())  # Output: Hello from Parent and Child
Python

Python Builtin Functions tuple: tuple constructor / type

Definition and Usage of Python builtin function tuple

Creates a new tuple object.

Syntax of Python builtin function tuple

Parameter Values of Python builtin function tuple

  • iterable: Optional iterable to initialize the tuple.

Example of Python builtin function tuple

Python Builtin Functions type: get type or create new type

Definition and Usage of Python builtin function type

Returns the type of an object or creates a new class.

Syntax of Python builtin function type

Parameter Values of Python builtin function type

  • object: An object.
  • name, bases, dict: Used for creating a new class.

Example of Python builtin function type

Python Builtin Functions vars: dict for an object or locals()

Definition and Usage of Python builtin function vars

Returns the __dict__ attribute of a module, class, or object.

Syntax of Python builtin function vars

Parameter Values of Python builtin function vars

  • object: Optional.

Example of Python builtin function vars

Python
class MyClass:
    x = 5

obj = MyClass()
print(vars(obj))      # Output: {}
print(vars(MyClass))  # Output: dictionary of class attributes
Python

Python Builtin Functions zip: aggregate elements from iterables

Definition and Usage of Python builtin function zip

Creates an iterator that aggregates elements from multiple iterables.

Syntax of Python builtin function zip

Parameter Values of Python builtin function zip

  • iterables: One or more iterables.

Example of Python builtin function zip

Python
l1 = [1, 2, 3]
l2 = ['a', 'b', 'c']
print(list(zip(l1, l2)))  # Output: [(1, 'a'), (2, 'b'), (3, 'c')]
Python

Python Builtin Functions __import__: low-level import function

Definition and Usage of Python builtin function __import__

A low-level function that is used to implement the import statement.

Syntax of Python builtin function __import__

Parameter Values of Python builtin function __import__

  • name: Name of the module.
  • globals: Optional globals dictionary.
  • locals: Optional locals dictionary.
  • fromlist: Optional list of attributes to import.
  • level: Specifies whether to use absolute or relative imports.

Example of Python builtin function __import__

Python
sys = __import__('sys')
print(sys.version_info)
Python

Python Builtin Values NotImplemented: special value used by rich comparisons

Definition and Usage of Python builtin value NotImplemented

A special value that should be returned by binary special methods (like __eq__, __add__, etc.) to indicate the operation is not implemented for the other type.

Syntax of Python builtin value NotImplemented

Parameter Values of Python builtin value NotImplemented

  • None.

Example of Python builtin value NotImplemented

Python
class MyClass:
    def __eq__(self, other):
        if isinstance(other, int):
            return self.value == other
        return NotImplemented
Python

Python Builtin Values Ellipsis: special singleton (…) used in slicing/typing

Definition and Usage of Python builtin value Ellipsis

The … syntax, used for special slicing and in type hints.

Syntax of Python builtin value Ellipsis

Parameter Values of Python builtin value Ellipsis

  • None.

Example of Python builtin value Ellipsis

Python
l = [[1, 2], [3, 4], [5, 6]]
print(l[...])  # Equivalent to l[:]
Python

Python Builtin Exceptions BaseException: root exception class

Definition and Usage of Python builtin exception BaseException

The base class for all built-in exceptions.

Syntax of Python builtin exception BaseException

Example of Python builtin exception BaseException

All other exceptions are subclasses of this.

Python Builtin Exceptions Exception: base class for most errors

Definition and Usage of Python builtin exception Exception

The base class for most non-fatal exceptions.

Syntax of Python builtin exception Exception

Example of Python builtin exception Exception

Python
try:
    raise Exception("An error occurred")
except Exception as e:
    print(e)
Python

Python Builtin Exceptions ArithmeticError: base class for numeric errors

Definition and Usage of Python builtin exception ArithmeticError

Base class for exceptions that occur during arithmetic calculations.

Syntax of Python builtin exception ArithmeticError

Example of Python builtin exception ArithmeticError

Includes exceptions like OverflowError, ZeroDivisionError.

Python Builtin Exceptions BufferError: buffer related error

Definition and Usage of Python builtin exception BufferError

Raised when a buffer-related operation cannot be performed.

Syntax of Python builtin exception BufferError

Example of Python builtin exception BufferError

Python
mv = memoryview(b"abc")
try:
    mv[0] = b'd'
except BufferError as e:
    print(e)
Python

Python Builtin Exceptions LookupError: base class for lookup errors

Definition and Usage of Python builtin exception LookupError

Base class for exceptions raised when a key or index used on a mapping or sequence is invalid.

Syntax of Python builtin exception LookupError

Example of Python builtin exception LookupError

Includes exceptions like KeyError and IndexError.

Python Builtin Exceptions AssertionError: failed assert statement

Definition and Usage of Python builtin exception AssertionError

Raised when an assert statement fails.

Syntax of Python builtin exception AssertionError

Example of Python builtin exception AssertionError

Python
try:
    assert 1 == 2
except AssertionError as e:
    print(e)
Python

Python Builtin Exceptions AttributeError: missing attribute access error

Definition and Usage of Python builtin exception AttributeError

Raised when an attribute reference or assignment fails.

Syntax of Python builtin exception AttributeError

Example of Python builtin exception AttributeError

Python
class MyClass:
    pass

try:
    MyClass().x
except AttributeError as e:
    print(e)
Python

Python Builtin Exceptions EOFError: end-of-file when reading input

Definition and Usage of Python builtin exception EOFError

Raised when one of the input() functions hits an end-of-file condition.

Syntax of Python builtin exception EOFError

Example of Python builtin exception EOFError

Python Builtin Exceptions FloatingPointError: floating point operation error

Definition and Usage of Python builtin exception FloatingPointError

Raised when a floating-point operation fails. Rarely occurs.

Syntax of Python builtin exception FloatingPointError

Example of Python builtin exception FloatingPointError

Python Builtin Exceptions GeneratorExit: raised when generator.close() is called

Definition and Usage of Python builtin exception GeneratorExit

Raised by a generator’s close() method to terminate the generator.

Syntax of Python builtin exception GeneratorExit

Example of Python builtin exception GeneratorExit

Python
def my_generator():
    try:
        yield 1
    finally:
        print("Generator closed")

gen = my_generator()
print(next(gen))
gen.close()
Python

Python Builtin Exceptions ImportError: import-related error

Definition and Usage of Python builtin exception ImportError

Raised when the import statement has trouble loading a module.

Syntax of Python builtin exception ImportError

Example of Python builtin exception ImportError

Python
try:
    import non_existent_module
except ImportError as e:
    print(e)
Python

Python Builtin Exceptions ModuleNotFoundError: module not found on import

Definition and Usage of Python builtin exception ModuleNotFoundError

A subclass of ImportError, raised when a module cannot be found.

Syntax of Python builtin exception ModuleNotFoundError

Example of Python builtin exception ModuleNotFoundError

Python
try:
    import non_existent_module
except ModuleNotFoundError as e:
    print(e)
Python

Python Builtin Exceptions IndexError: sequence index out of range

Definition and Usage of Python builtin exception IndexError

Raised when a sequence index is out of range.

Syntax of Python builtin exception IndexError

Example of Python builtin exception IndexError

Python
l = [1, 2]
try:
    print(l[2])
except IndexError as e:
    print(e)
Python

Python Builtin Exceptions KeyError: mapping key not found

Definition and Usage of Python builtin exception KeyError

Raised when a dictionary key is not found.

Syntax of Python builtin exception KeyError

Example of Python builtin exception KeyError

Python
d = {'a': 1}
try:
    print(d['b'])
except KeyError as e:
    print(e)
Python

Python Builtin Exceptions KeyboardInterrupt: user interruption (Ctrl+C)

Definition and Usage of Python builtin exception KeyboardInterrupt

Raised when the user hits the interrupt key (usually Ctrl+C).

Syntax of Python builtin exception KeyboardInterrupt

Example of Python builtin exception KeyboardInterrupt

Python Builtin Exceptions MemoryError: out of memory

Definition and Usage of Python builtin exception MemoryError

Raised when an operation runs out of memory.

Syntax of Python builtin exception MemoryError

Example of Python builtin exception MemoryError

Python Builtin Exceptions NameError: name not found in local/global scope

Definition and Usage of Python builtin exception NameError

Raised when a local or global name is not found.

Syntax of Python builtin exception NameError

Example of Python builtin exception NameError

Python
try:
    print(non_existent_variable)
except NameError as e:
    print(e)
Python

Python Builtin Exceptions NotImplementedError: method abstract/not implemented

Definition and Usage of Python builtin exception NotImplementedError

Raised when an abstract method is not implemented in a subclass.

Syntax of Python builtin exception NotImplementedError

Example of Python builtin exception NotImplementedError

Python
class Base:
    def my_method(self):
        raise NotImplementedError

class Sub(Base):
    pass

try:
    Sub().my_method()
except NotImplementedError as e:
    print(e)
Python

Python Builtin Exceptions OSError: OS related error (file, network, etc.)

Definition and Usage of Python builtin exception OSError

Raised for system-related errors, such as I/O failures.

Syntax of Python builtin exception OSError

Example of Python builtin exception OSError

Python Builtin Exceptions OverflowError: arithmetic result too large to represent

Definition and Usage of Python builtin exception OverflowError

Raised when an arithmetic operation’s result is too large to be represented.
(Note: standard integers in Python can handle arbitrary size).

Syntax of Python builtin exception OverflowError

Example of Python builtin exception OverflowError

Python
import math
try:
    print(math.exp(1000))
except OverflowError as e:
    print(e)
Python

Conclusion: Summary of Python Builtin Functions, Values, and Exceptions

Python’s built-in functions, values, and exceptions form the core of the language, providing essential tools for efficient programming without the need for external libraries. These built-ins span multiple categories:

  1. Utility Functions — such as getattr(), setattr(), hasattr(), len(), and type(), which enable inspection, modification, and validation of objects and their attributes. These functions help developers dynamically interact with data structures and objects.
  2. Type Constructors and Conversions — including int(), str(), list(), tuple(), set(), and dict(), which allow type conversion, creation of collections, and structured data management in an intuitive way.
  3. Iterators and Functional Tools — like iter(), next(), map(), filter(), zip(), and enumerate() which streamline sequence processing and functional programming paradigms, improving both performance and readability.
  4. Mathematical Functions — such as abs(), min(), max(), sum(), round(), pow(), and hash(), which provide efficient numeric computation and data evaluation.
  5. System and Environment Interaction — including globals(), locals(), dir(), help(), and __import__() which enable inspection of the runtime environment, dynamic module imports, and access to global and local symbol tables.
  6. Special Values — NotImplemented and Ellipsis, which serve specialized roles in object protocols and slicing operations, adding flexibility for advanced developers.
  7. Exceptions — a comprehensive set of built-in exception classes like ValueError, TypeError, AttributeError, IndexError, and KeyError, which empower robust error handling. These exception classes form the foundation for Python’s error-reporting system, enabling developers to write safer, cleaner, and more maintainable code.

Key Takeaways:

  • Python built-ins provide ease of use, speed, and consistency, allowing developers to focus on solving problems rather than reimplementing common functionality.
  • Mastery of these built-ins leads to better code quality, improved readability, and optimized performance.
  • They act as a foundational toolkit, allowing developers to build complex applications efficiently while maintaining code clarity and reliability.

In short, Python built-ins are indispensable tools that transform the way developers work — providing both power and simplicity in a single package.

Top 20 Interview Questions on Python Built-in Functions

What are Python built-in functions?

Python built-in functions are predefined functions provided by Python, available without importing any library. Examples: print(), len(), type().

How many built-in functions are available in Python 3?

Python 3.11 includes 69 built-in functions.

What is the difference between built-in and user-defined functions?

Built-in: Already provided by Python (e.g., abs(), sum()).
User-defined: Created by developers using def or lambda.

Why are built-in functions faster than user-defined ones?

Built-ins are written in C (for CPython) and optimized for speed, making them faster than equivalent Python code.

Can we override Python built-in functions?

Yes, but it’s not recommended. For example:

len = 5 print(len([1,2,3])) # Error: ‘int’ object is not callable

What does the dir() function do?

dir() returns a list of all attributes and methods of an object.

What is the difference between globals() and locals()?

globals(): Returns dictionary of current global variables.
locals(): Returns dictionary of local variables within a function.

How is eval() different from exec()?

eval(): Evaluates a Python expression and returns a result.
exec(): Executes a block of Python code but doesn’t return anything.

What does the enumerate() function do?

It adds an index to iterable elements.

for i, v in enumerate([‘a’,’b’]): print(i, v) # 0 a # 1 b

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