Python comes with a number of useful builtin functions, we can use these functions directly by simply calling them. Some of the most popular such functions includes print(), len(), range(), e.t.c

In the latest versions of Python, there is a total of 69 builtin functions. This is not including the functions that exists in the various modules of the standard library.

To use any of the builtin functions, we simply call them without performing any extra importation all installation, for example we can use the len() function to get the number of elements in a collection such as list, tuple, e.t.c

using a builtin function 

collection = ['Java', 'Python', 'PHP']

print(len(collection)) #call the len function to get the number of elements

In the above example, we have actually used two builtin functions. The len() function to get the number of elements in the list and  the print() function to display the length on the console.

The cheatseat

In the following table, each of the the builtin functions is listed together with its purpose.

Function Purpose
abs(x) Returns the absolute value of x.
aiter() Creates asynchronous iterator for an async iterable object.
all(iterable) Checks whether all elements in the given iterable have a boolean value of True.
anext() Retrieves the next value in an asynchronous iterator.
any(iterable) Checks if there is any  value in the given iterable with a boolean value of True
ascii(obj) Returns the ASCII representation of the given object
bin(x) Converts an integer to the equivalent binary string(base 2), preceded by “0b”.
bool(obj) Returns the boolean representation(True or False) of the given object.
breakpoint() Pauses the execution and enters the interactive debugger(Pdb).
bytearray(source = None, encoding = 'utf-8', errors = 'strict') A constructor function for creating an array of bytes. With no argument, it creates an empty array. If an iterable is given as argument, it uses the elements of the iterable for initial data in the array of bytes.
bytes(source = None, encoding = 'utf-8', errors='strict') Creates and returns a bytes object from the given source. If no source is given, an empty bytes object is returned. 
callable(obj) Checks if the given object is callable. Returns True if it is callable and False otherwise.
chr(integer_code) Returns a string representing a character from the given Unicode code integer. e.g chr(97) => 'a'
@classmethod A decorator function that is used to create class methods. 
compile(source, filename = '<string>', mode='exec') Compiles a source string into a code object which can then be executed with either exec() or eval().
complex(a, b = 0) Constructs a complex number given its real(a) and imaginary(b) parts. 
delattr(obj, attr) Delete the specified attribute(attr) from the namespace of the given object(obj).

A constructor for dictionary objects. Without any argument, the function returns an empty dictionary. It can be used with arguments to create a dictionary from the items of an existing dictionary/mapping. 

dir(obj) Returns the list of names that are defined or associated with a given namespace or object.
divmod(a, b) Returns the quotient and the remainder after dividing the two numbers given as arguments i.e a and b.
enumerate(iterable, start = 0) Returns index-value pairs, where the value is an element from the iterable and the index is its index. The start argument can be set to modify the starting point of the indexes.
eval(expression) Evaluates an expression passed in as a string, or as a code object generated by the compile function. 
exec(source, globals = None, locals = None) Executes the arbitrary Python object given in the source arguments. source can be a string or a code object generated by the compile function. 
filter(function, iterable) Filters the elements of the iterable by calling the given function with each of the iterable's element. It returns an iterator of only those elements that evaluate to True.
float(obj = None) The constructor function for float type. If no argument is given, it returns 0.0. Otherwise, it turns the given object into the equivalent floating point representation
format() Used for formatting strings.
frozenset(iterable = None) A constructor for frozenset objects.
getattr(obj, attr) Retrieves  the value of the  specified attribute(attr) of the given object, obj. It is the functional equivalent of the dot notation as in obj.attr 
globals() Returns the global symbol table as a dictionary.
hasattr(obj, name) Checks whether the given object(obj) has an attribute with the specified name. Returns True if the attribute exist and False otherwise.
hash(obj) Returns the hash value of the given object in the current Python process.
help() Starts the interactive help system. It can be called with arguments to get help on specific objects, keywords, modules e.t.c  e.g help('while') to get help on the while keyword.
hex(x) Converts an integer number to the equivalent hexadecimal string(base 16), prefixed by '0x'
id(obj) Returns the memory address of the given object within  the current Python process.
input(prompt = None) Takes input from the user. prompt is the optional message that will be shown to the user. 
int(x) Converts an object of a supported type into an integer. e.g int("10") to convert the string "10"  to integer 10.
isinstance(obj, type) Checks whether the given object is an instance of the specified type. True of so and False otherwise.
issubclass(cls, parent) Checks whether the first class(cls) is a sub class of the other(parent)
iter(iterable) Creates an iterator for iterating through the elements of the iterable.
len(iterable) Returns the number of elements present in an iterable object, such as a string, list, dictionary, range, etc.
list(iterable = None) A constructor for lists. If no argument is given, it returns an empty list. If an iterable is given as argument, its element will be used as the initial elements of the created list.
locals() Returns a dictionary containing the mapping between the variables defined in the current local scope and their values.
map(function, iterable) Applies the given function to each item of the iterable.
max(iterable, *args, key = None, default = None) Returns the largest value in the iterable.
min(iterable, *args, key = None, default=None) Returns the smallest value in the given iterable.
next(iterator) Retrieves the next item of an iterator object. If the iterator is empty, the function raises a StopIteration exception.
object() A constructor function for base objects
oct(x) Converts integer x to the equivalent string octal(base 8), prefixed with "0o".
open() Open a file for reading or writing or both.
ord(char) returns the Unicode integer code of the specified character
pow(x, y) Returns the resulting value after raising x to the power of y. e.g pow(2, 4) => 16
print(*args) Outputs the given objects to an output stream such as the console.
@property A decorator function for creating properties.
repr(obj)  Returns the printable string representation of an object.
reversed(iterable) Returns a reverse iterator of the input iterable.
round(number, ndgits = 0) Round a number to a specified number of decimal places. It returns a floating point number rounded off to the given digits precision.
set(iterable = None) The constructor function for sets. If no argument is given it returns an empty set. If an iterable is given, the initial elements of the created set will be obtained from the iterable,
setattr(obj, name, value) Dynamically sets the value of an object's attribute, given the object, the attribute's name and the value to be set to the attribute.
slice( stop, start = 0, step = 1) Creates a slice object that represents the set of indices specified by range(start, stop, step).
sorted(iterable) Returns a sorted list of the elements from the given iterable
@staticmethod  A decorator function for creating static methods.
str(obj = None) Returns the string representation of the given object. If no argument is given, it returns an empty string.
sum(iterable) Calculates the sum of the elements of the given iterable. e.g sum([4, 5, 6]) =>15
super(cls) Used to access the superclasses of a given class in the inheritance hierarchy
tuple(iterable = None) The constructor function for tuples. If no argument is given, it returns an empty tuple. If an iterable is given, the initial elements of the created tuple will be obtained from the iterable.
type(obj) Returns the type/class of the given object.
vars(obj) Returns the __dict__ attribute of an object, a class, a module e.t.c.
zip(*iterables) Combines two or more iterables into an iterator of tuples, where each tuple contains the elements in the corresponding indices of the iterables.
__import__() Used to dynamically load modules into the program. e.g __import__("math") to load the math module.