Built-in Functions

The Python built-in functions are defined as the functions whose functionality is pre-defined in Python. The python interpreter has several functions that are always present for use. These functions are known as Built-in Functions. There are several built-in functions in Python which are listed below:

Python abs() Function

The python abs() function is used to return the absolute value of a number. It takes only one argument, a number whose absolute value is to be returned. The argument can be an integer and floating-point number. If the argument is a complex number, then, abs() returns its magnitude.

Python abs() Function Example

#  integer number	
integer = -20
print('Absolute value of -40 is:', abs(integer))

#  floating number
floating = -20.83
print('Absolute value of -40.83 is:', abs(floating))

Python all() Function

The python all() function accepts an iterable object (such as list, dictionary, etc.). It returns true if all items in passed iterable are true. Otherwise, it returns False. If the iterable object is empty, the all() function returns True.

Python all() Function Example

# all values true
k = [1, 3, 4, 6]
print(all(k))

# all values false
k = [0, False]
print(all(k))

# one false value
k = [1, 3, 7, 0]
print(all(k))

# one true value
k = [0, False, 5]
print(all(k))

# empty iterable
k = []
print(all(k))

Python bin() Function

The python bin() function is used to return the binary representation of a specified integer. A result always starts with the prefix 0b.

Python bin() Function Example

x =  10
y =  bin(x)
print (y)

Python bool()

The python bool() converts a value to boolean(True or False) using the standard truth testing procedure.

Python bool() Example

test1 = []
print(test1,'is',bool(test1))
test1 = [0]
print(test1,'is',bool(test1))
test1 = 0.0
print(test1,'is',bool(test1))
test1 = None
print(test1,'is',bool(test1))
test1 = True
print(test1,'is',bool(test1))
test1 = 'Easy string'
print(test1,'is',bool(test1))

Python bytes()

The python bytes() in Python is used for returning a bytes object. It is an immutable version of the bytearray() function.

It can create empty bytes object of the specified size.

Python bytes() Example

string = "Hello World."
array = bytes(string, 'utf-8')
print(array)

Python callable() Function

A python callable() function in Python is something that can be called. This built-in function checks and returns true if the object passed appears to be callable, otherwise false.

Python callable() Function Example

x = 8
print(callable(x))

Python compile() Function

The python compile() function takes source code as input and returns a code object which can later be executed by exec() function.

Python compile() Function Example

# compile string source to code
code_str = 'x=5\ny=10\nprint("sum =",x+y)'
code = compile(code_str, 'sum.py', 'exec')
print(type(code))
exec(code)
exec(x)

Python exec() Function

The python exec() function is used for the dynamic execution of Python program which can either be a string or object code and it accepts large blocks of code, unlike the eval() function which only accepts a single expression.

Python exec() Function Example

x = 8
exec('print(x==8)')
exec('print(x+4)')

Python sum() Function

As the name says, python sum() function is used to get the sum of numbers of an iterable, i.e., list.

Python sum() Function Example

s = sum([1, 2,4 ])
print(s)

s = sum([1, 2, 4], 10)
print(s)

Python any() Function

The python any() function returns true if any item in an iterable is true. Otherwise, it returns False.

Python any() Function Example

l = [4, 3, 2, 0]                            
print(any(l))                                 

l = [0, False]
print(any(l))

l = [0, False, 5]
print(any(l))

l = []
print(any(l))

Python ascii() Function

The python ascii() function returns a string containing a printable representation of an object and escapes the non-ASCII characters in the string using \x, \u or \U escapes.

Python ascii() Function Example

normalText = 'Python is interesting'
print(ascii(normalText))

otherText = 'Pythön is interesting'
print(ascii(otherText))

print('Pyth\xf6n is interesting')

Python bytearray()

The python bytearray() returns a bytearray object and can convert objects into bytearray objects, or create an empty bytearray object of the specified size.

Python bytearray() Example

string = "Python is a programming language."

# string with encoding 'utf-8'
arr = bytearray(string, 'utf-8')
print(arr)

Python eval() Function

The python eval() function parses the expression passed to it and runs python expression(code) within the program.

Python eval() Function Example

x = 8
print(eval('x + 1'))

Python float()

The python float() function returns a floating-point number from a number or string.

Python float() Example

# for integers
print(float(9))

# for floats
print(float(8.19))

# for string floats
print(float("-24.27"))

# for string floats with whitespaces
print(float("     -17.19\n"))

# string float error
print(float("xyz"))

Python format() Function

The python format() function returns a formatted representation of the given value.

Python format() Function Example

# d, f and b are a type

# integer
print(format(123, "d"))

# float arguments
print(format(123.4567898, "f"))

# binary format
print(format(12, "b"))

Python frozenset()

The python frozenset() function returns an immutable frozenset object initialized with elements from the given iterable.

Python frozenset() Example

# tuple of letters
letters = ('m', 'r', 'o', 't', 's')

fSet = frozenset(letters)
print('Frozen set is:', fSet)
print('Empty frozen set is:', frozenset())

Python getattr() Function

The python getattr() function returns the value of a named attribute of an object. If it is not found, it returns the default value.

Python getattr() Function Example

class Details:
    age = 22
    name = "Phill"

details = Details()
print('The age is:', getattr(details, "age"))
print('The age is:', details.age)

Python globals() Function

The python globals() function returns the dictionary of the current global symbol table.

A Symbol table is defined as a data structure which contains all the necessary information about the program. It includes variable names, methods, classes, etc.

Python globals() Function Example

age = 22

globals()['age'] = 22
print('The age is:', age)

Python hasattr() Function

The python any() function returns true if any item in an iterable is true, otherwise it returns False.

Python hasattr() Function Example

l = [4, 3, 2, 0]                            
print(any(l))                                 

l = [0, False]
print(any(l))

l = [0, False, 5]
print(any(l))

l = []
print(any(l))

Python iter() Function

The python iter() function is used to return an iterator object. It creates an object which can be iterated one element at a time.

Python iter() Function Example

# list of numbers
list = [1,2,3,4,5]

listIter = iter(list)

# prints '1'
print(next(listIter))

# prints '2'
print(next(listIter))

# prints '3'
print(next(listIter))

# prints '4'
print(next(listIter))

# prints '5'
print(next(listIter))

Python len() Function

The python len() function is used to return the length (the number of items) of an object.

Python len() Function Example

strA = 'Python'
print(len(strA))

Python list()

The python list() creates a list in python.

Python list() Example

# empty list
print(list())

# string
String = 'abcde'     
print(list(String))

# tuple
Tuple = (1,2,3,4,5)
print(list(Tuple))
# list
List = [1,2,3,4,5]
print(list(List))

Python locals() Function

The python locals() method updates and returns the dictionary of the current local symbol table.

A Symbol table is defined as a data structure which contains all the necessary information about the program. It includes variable names, methods, classes, etc.

Python locals() Function Example

def localsAbsent():
    return locals()

def localsPresent():
    present = True
    return locals()

print('localsNotPresent:', localsAbsent())
print('localsPresent:', localsPresent())

Python map() Function

The python map() function is used to return a list of results after applying a given function to each item of an iterable(list, tuple etc.).

Python map() Function Example

def calculateAddition(n):
  return n+n

numbers = (1, 2, 3, 4)
result = map(calculateAddition, numbers)
print(result)

# converting map object to set
numbersAddition = set(result)
print(numbersAddition)

Python memoryview() Function

The python memoryview() function returns a memoryview object of the given argument.

Python memoryview () Function Example

#A random bytearray
randomByteArray = bytearray('ABC', 'utf-8')

mv = memoryview(randomByteArray)

# access the memory view's zeroth index
print(mv[0])

# It create byte from memory view
print(bytes(mv[0:2]))

# It create list from memory view
print(list(mv[0:3]))

Python object()

The python object() returns an empty object. It is a base for all the classes and holds the built-in properties and methods which are default for all the classes.

Python object() Example

python = object()

print(type(python))
print(dir(python))

Python open() Function

The python open() function opens the file and returns a corresponding file object.

Python open() Function Example

# opens python.text file of the current directory
f = open("python.txt")
# specifying full path
f = open("C:/Python33/README.txt")

Python chr() Function

Python chr() function is used to get a string representing a character which points to a Unicode code integer. For example, chr(97) returns the string 'a'. This function takes an integer argument and throws an error if it exceeds the specified range. The standard range of the argument is from 0 to 1,114,111.

Python chr() Function Example

# Calling function
result = chr(102) # It returns string representation of a char
result2 = chr(112)
# Displaying result
print(result)
print(result2)
# Verify, is it string type?
print("is it string type:", type(result) is str)

Python complex()

Python complex() function is used to convert numbers or string into a complex number. This method takes two optional parameters and returns a complex number. The first parameter is called a real and second as imaginary parts.

Python complex() Example

# Python complex() function example
# Calling function
a = complex(1) # Passing single parameter
b = complex(1,2) # Passing both parameters
# Displaying result
print(a)
print(b)

Python delattr() Function

Python delattr() function is used to delete an attribute from a class. It takes two parameters, first is an object of the class and second is an attribute which we want to delete. After deleting the attribute, it no longer available in the class and throws an error if try to call it using the class object.

Python delattr() Function Example

class Student:
    id = 101
    name = "Pranshu"
    email = "pranshu@abc.com"
# Declaring function
    def getinfo(self):
        print(self.id, self.name, self.email)
s = Student()
s.getinfo()
delattr(Student,'course') # Removing attribute which is not available
s.getinfo() # error: throws an error

Python dir() Function

Python dir() function returns the list of names in the current local scope. If the object on which method is called has a method named __dir__(), this method will be called and must return the list of attributes. It takes a single object type argument.

Python dir() Function Example

# Calling function
att = dir()
# Displaying result
print(att)

Python divmod() Function

Python divmod() function is used to get remainder and quotient of two numbers. This function takes two numeric arguments and returns a tuple. Both arguments are required and numeric

Python divmod() Function Example

# Python divmod() function example
# Calling function
result = divmod(10,2)
# Displaying result
print(result)

Python enumerate() Function

Python enumerate() function returns an enumerated object. It takes two parameters, first is a sequence of elements and the second is the start index of the sequence. We can get the elements in sequence either through a loop or next() method.

Python enumerate() Function Example

# Calling function
result = enumerate([1,2,3])
# Displaying result
print(result)
print(list(result))

Python dict()

Python dict() function is a constructor which creates a dictionary. Python dictionary provides three different constructors to create a dictionary:

• If no argument is passed, it creates an empty dictionary.
• If a positional argument is given, a dictionary is created with the same key-value pairs. Otherwise, pass an iterable object.
• If keyword arguments are given, the keyword arguments and their values are added to the dictionary created from the positional argument.

Python dict() Example

# Calling function
result = dict() # returns an empty dictionary
result2 = dict(a=1,b=2)
# Displaying result
print(result)
print(result2)

Python filter() Function

Python filter() function is used to get filtered elements. This function takes two arguments, first is a function and the second is iterable. The filter function returns a sequence of those elements of iterable object for which function returns true value.

The first argument can be none, if the function is not available and returns only elements that are true.

Python filter() Function Example

# Python filter() function example
def filterdata(x):
    if x>5:
        return x
# Calling function
result = filter(filterdata,(1,2,6))
# Displaying result
print(list(result))

Python hash() Function

Python hash() function is used to get the hash value of an object. Python calculates the hash value by using the hash algorithm. The hash values are integers and used to compare dictionary keys during a dictionary lookup. We can hash only the types which are given below:

Hashable types: * bool * int * long * float * string * Unicode * tuple * code object.

Python hash() Function Example

# Calling function
result = hash(21) # integer value
result2 = hash(22.2) # decimal value
# Displaying result
print(result)
print(result2)

Python help() Function

Python help() function is used to get help related to the object passed during the call. It takes an optional parameter and returns help information. If no argument is given, it shows the Python help console. It internally calls python's help function.

Python help() Function Example

# Calling function
info = help() # No argument
# Displaying result
print(info)

Python min() Function

Python min() function is used to get the smallest element from the collection. This function takes two arguments, first is a collection of elements and second is key, and returns the smallest element from the collection.

Python min() Function Example

# Calling function
small = min(2225,325,2025) # returns smallest element
small2 = min(1000.25,2025.35,5625.36,10052.50)
# Displaying result
print(small)
print(small2)

Python set() Function

In python, a set is a built-in class, and this function is a constructor of this class. It is used to create a new set using elements passed during the call. It takes an iterable object as an argument and returns a new set object.

Python set() Function Example

# Calling function
result = set() # empty set
result2 = set('12')
result3 = set('rookienerd')
# Displaying result
print(result)
print(result2)
print(result3)

Python hex() Function

Python hex() function is used to generate hex value of an integer argument. It takes an integer argument and returns an integer converted into a hexadecimal string. In case, we want to get a hexadecimal value of a float, then use float.hex() function.

Python hex() Function Example

# Calling function
result = hex(1) 
# integer value
result2 = hex(342) 
# Displaying result
print(result)
print(result2)

Python id() Function

Python id() function returns the identity of an object. This is an integer which is guaranteed to be unique. This function takes an argument as an object and returns a unique integer number which represents identity. Two objects with non-overlapping lifetimes may have the same id() value.

Python id() Function Example

# Calling function
val = id("rookienerd") # string object
val2 = id(1200) # integer object
val3 = id([25,336,95,236,92,3225]) # List object
# Displaying result
print(val)
print(val2)
print(val3)

Python setattr() Function

Python setattr() function is used to set a value to the object's attribute. It takes three arguments, i.e., an object, a string, and an arbitrary value, and returns none. It is helpful when we want to add a new attribute to an object and set a value to it.

Python setattr() Function Example

class Student:
    id = 0
    name = ""
    
    def __init__(self, id, name):
        self.id = id
        self.name = name
        
student = Student(102,"Sohan")
print(student.id)
print(student.name)
#print(student.email) product error
setattr(student, 'email','sohan@abc.com') # adding new attribute
print(student.email)

Python slice() Function

Python slice() function is used to get a slice of elements from the collection of elements. Python provides two overloaded slice functions. The first function takes a single argument while the second function takes three arguments and returns a slice object. This slice object can be used to get a subsection of the collection.

Python slice() Function Example

# Calling function
result = slice(5) # returns slice object
result2 = slice(0,5,3) # returns slice object
# Displaying result
print(result)
print(result2)

Python sorted() Function

Python sorted() function is used to sort elements. By default, it sorts elements in an ascending order but can be sorted in descending also. It takes four arguments and returns a collection in sorted order. In the case of a dictionary, it sorts only keys, not values.

Python sorted() Function Example

str = "rookienerd" # declaring string
# Calling function
sorted1 = sorted(str) # sorting string
# Displaying result
print(sorted1)

Python next() Function

Python next() function is used to fetch next item from the collection. It takes two arguments, i.e., an iterator and a default value, and returns an element.

This method calls on iterator and throws an error if no item is present. To avoid the error, we can set a default value.

Python next() Function Example

number = iter([256, 32, 82]) # Creating iterator
# Calling function
item = next(number) 
# Displaying result
print(item)
# second item
item = next(number)
print(item)
# third item
item = next(number)
print(item)

Python input() Function

Python input() function is used to get an input from the user. It prompts for the user input and reads a line. After reading data, it converts it into a string and returns it. It throws an error EOFError if EOF is read.

Python input() Function Example

# Calling function
val = input("Enter a value: ")
# Displaying result
print("You entered:",val)

Python int() Function

Python int() function is used to get an integer value. It returns an expression converted into an integer number. If the argument is a floating-point, the conversion truncates the number. If the argument is outside the integer range, then it converts the number into a long type.

If the number is not a number or if a base is given, the number must be a string.

Python int() Function Example

# Calling function
val = int(10) # integer value
val2 = int(10.52) # float value
val3 = int('10') # string value
# Displaying result
print("integer values :",val, val2, val3)

Python isinstance() Function

Python isinstance() function is used to check whether the given object is an instance of that class. If the object belongs to the class, it returns true. Otherwise returns False. It also returns true if the class is a subclass.

The isinstance() function takes two arguments, i.e., object and classinfo, and then it returns either True or False.

Python isinstance() function Example

class Student:
    id = 101
    name = "John"
    def __init__(self, id, name):
        self.id=id
        self.name=name

student = Student(1010,"John")
lst = [12,34,5,6,767]
# Calling function 
print(isinstance(student, Student)) # isinstance of Student class
print(isinstance(lst, Student))

Python oct() Function

Python oct() function is used to get an octal value of an integer number. This method takes an argument and returns an integer converted into an octal string. It throws an error TypeError, if argument type is other than an integer.

Python oct() function Example

# Calling function
val = oct(10)
# Displaying result
print("Octal value of 10:",val)

Python ord() Function

The python ord() function returns an integer representing Unicode code point for the given Unicode character.

Python ord() function Example

# Code point of an integer
print(ord('8'))

# Code point of an alphabet 
print(ord('R'))

# Code point of a character
print(ord('&'))

Python pow() Function

The python pow() function is used to compute the power of a number. It returns x to the power of y. If the third argument(z) is given, it returns x to the power of y modulus z, i.e. (x, y) % z.

Python pow() function Example

# positive x, positive y (x**y)
print(pow(4, 2))

# negative x, positive y
print(pow(-4, 2))

# positive x, negative y (x**-y)
print(pow(4, -2))

# negative x, negative y
print(pow(-4, -2))

Python print() Function

The python print() function prints the given object to the screen or other standard output devices.

Python print() function Example

print("Python is programming language.")

x = 7
# Two objects passed
print("x =", x)

y = x
# Three objects passed
print('x =', x, '= y')

Python range() Function

The python range() function returns an immutable sequence of numbers starting from 0 by default, increments by 1 (by default) and ends at a specified number.

Python range() function Example

# empty range
print(list(range(0)))

# using the range(stop)
print(list(range(4)))

# using the range(start, stop)
print(list(range(1,7 )))

Python reversed() Function

The python reversed() function returns the reversed iterator of the given sequence.

Python reversed() function Example

# for string
String = 'Java'
print(list(reversed(String)))

# for tuple
Tuple = ('J', 'a', 'v', 'a')
print(list(reversed(Tuple)))

# for range
Range = range(8, 12)
print(list(reversed(Range)))

# for list
List = [1, 2, 7, 5]
print(list(reversed(List)))

Python round() Function

The python round() function rounds off the digits of a number and returns the floating point number.

Python round() Function Example

#  for integers
print(round(10))

#  for floating point
print(round(10.8))

#  even choice
print(round(6.6))

Python issubclass() Function

The python issubclass() function returns true if object argument(first argument) is a subclass of second class(second argument).

Python issubclass() Function Example

class Rectangle:
  def __init__(rectangleType):
    print('Rectangle is a ', rectangleType)

class Square(Rectangle):
  def __init__(self):
    Rectangle.__init__('square')
    
print(issubclass(Square, Rectangle))
print(issubclass(Square, list))
print(issubclass(Square, (list, Rectangle)))
print(issubclass(Rectangle, (list, Rectangle)))

Python str

The python str() converts a specified value into a string.

Python str() Function Example

str('4')

Python tuple() Function

The python tuple() function is used to create a tuple object.

Python tuple() Function Example

t1 = tuple()
print('t1=', t1)

# creating a tuple from a list
t2 = tuple([1, 6, 9])
print('t2=', t2)

# creating a tuple from a string
t1 = tuple('Java')
print('t1=',t1)

# creating a tuple from a dictionary
t1 = tuple({4: 'four', 5: 'five'})
print('t1=',t1)

Python type()

The python type() returns the type of the specified object if a single argument is passed to the type() built in function. If three arguments are passed, then it returns a new type object.

Python type() Function Example

List = [4, 5]
print(type(List))

Dict = {4: 'four', 5: 'five'}
print(type(Dict))

class Python:
    a = 0

InstanceOfPython = Python()
print(type(InstanceOfPython))

Python vars() function

The python vars() function returns the __dict__ attribute of the given object.

Python vars() Function Example

class Python:
  def __init__(self, x = 7, y = 9):
    self.x = x
    self.y = y
  
InstanceOfPython = Python()
print(vars(InstanceOfPython))

Python zip() Function

The python zip() Function returns a zip object, which maps a similar index of multiple containers. It takes iterables (can be zero or more), makes it an iterator that aggregates the elements based on iterables passed, and returns an iterator of tuples.

Python zip() Function Example

numList = [4,5, 6]
strList = ['four', 'five', 'six']

# No iterables are passed
result = zip()

# Converting itertor to list
resultList = list(result)
print(resultList)

# Two iterables are passed
result = zip(numList, strList)

# Converting itertor to set
resultSet = set(result)
print(resultSet)