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Dec 14, 2019 in Python

Q: python built in function

1 Answer

Dec 14, 2019

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))  

Output:

Absolute value of -20 is: 20

Absolute value of -20.83 is: 20.83

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))  

Output:

True

False

False

False

True

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)  

Output:

0b1010

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))  

Output:

[] is False

[0] is True

0.0 is False

None is False

True is True

Easy string is True

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)  

Output:

b ' Hello World.'

Dec 14, 2019

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))  

Output:

False

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)  

Output:

<class 'code'>

sum = 15

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)')  

Output:

True

12

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)  

Output:

7

17

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))  

Output:

True

False

True

False

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')  

Output:

'Python is interesting'

'Pyth\xf6n is interesting'

Pythön 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)  

Output:

bytearray(b'Python is a programming language.')

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'))  

Output:

9

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"))  

Output:

9.0

8.19

-24.27

-17.19

ValueError: could not convert string to 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"))  

Output:

123

123.456790

1100

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())  

Output:

Frozen set is: frozenset({'o', 'm', 's', 'r', 't'})

Empty frozen set is: frozenset()

Dec 14, 2019
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)  

Output:

The age is: 22

The age is: 22

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)  

Output:

The age is: 22

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))  

Output:

True

False

True

False

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))  

Output:

1

2

3

4

5

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))  

Output:

6

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))  

Output:

[]

['a', 'b', 'c', 'd', 'e']

[1,2,3,4,5]

[1,2,3,4,5]

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())  

Output:

localsAbsent: {}

localsPresent: {'present': True}

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)  

Output:

<map object at 0x7fb04a6bec18>

{8, 2, 4, 6}

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]))  

Output:

65

b'AB'

[65, 66, 67]

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))  

Output:

<class 'object'>

['__class__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__',

'__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', '__ne__',

'__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__',

'__str__', '__subclasshook__']

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")  

Output:

Since the mode is omitted, the file is opened in 'r' mode; opens for reading.

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)  

Output:

ValueError: chr() arg not in range(0x110000)

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)  

Output:

(1.5+0j)

(1.5+2.2j)

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 = "[email protected]"  

# 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  

Output:

101 Pranshu [email protected]

AttributeError: course

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)  

Output:

['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__',

'__name__', '__package__', '__spec__']

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)  

Output:

(5, 0)

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))  

Output:

<enumerate object at 0x7ff641093d80>

[(0, 1), (1, 2), (2, 3)]

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)  

Output:

{}

{'a': 1, 'b': 2}

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))  

Output:

[6]

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.
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