Python built-in functions with program

Python Built-in Functions

Built-in functions are pre-defined in the programming language’s library, for the programming to directly call the functions wherever required in the program for achieving certain functional operations. A few of the frequently used built-in function in the Python programs are abs(x) for fetching the absolute value of x, bin() for getting the binary value, bool() for retrieving the boolean value of an object, list() for lists, len() to get the length of the value, open() to open the files, pow() for returning the power of a number, sum() for fetching the sum of the elements, reversed() for reversing the order, etc.

1. abs(x)

Returns the absolute value of a number. In case a complex number is passed, the magnitude of that number is returned. It is the same as the distance from the origin of a point on an x-y graph. For e.g.-

Abs(-3) =3

abs(3+4i) = 5

Code:

a = 12
b = -4
c = 3+4j
d = 7.90
print(abs(a))
print(abs(b))
print(abs(c))
print(abs(d))

Output:

Python Built in Functions output 1

2. all(x)

Same as logical ‘and’ operator. That means it will return true if all variables in the iterator are true. Here iterable objects are referred to as tuple, lists, dictionary.

A variable is said to be true in python if it is non-zero and not NONE. Here NONE is a keyword defined in python that is considered null.

For eg= if iterable ‘item’ contains value ‘2,4,5,6,1’ – Result will be true .

If item1= ‘2,0,4,5’ – Result will be false

Code:

tuple = (0, True, False)
x = all(tuple)
print(x)

output:

Python Built in Functions output 2

Explanation – Here, all() returns False because the first and third value in the tuple is false.

Code:

sampledict = {0 : "Apple", 1 : "Orange"}
x = all(sampledict)
print(x)

output:

Explanation- Here, all() returns False because one of the keys is false, and in the case of dictionaries, only the keys are checked, not the values.

3. any(x)

This function is the same as the logical ‘OR’ operator that returns False only if all the variables present in an iterable are false. Here iterable refers to the tuple, dictionary, and lists.

Note- For an empty iterable object, any() returns False.

For example- any(2,3,4,5,9) – True

Any(2,0,9,1,8) – Returns False

Code:

myset = {0, 1, 0}
x = any(myset)
print(x)

Output:

Explanation- In the above program, any function returns True, the set is given is having at least one True value.

4. bin()

This function returns the binary value of a number.

Code:

a=5
print(bin(a))

Output:

Python Built in Functions output 5

5. round()

It gives a roundoff value for a number, i.e. gives the nearest integer value for a number. This function accepts one argument, either decimal, float or integer and gives roundoff output.

Code:

print(round(4.5))
print(round(-7.7))

Output:

Python Built in Functions output 6

6. bin()

It returns the binary value for the number passed in the argument. The only integer can be passed as an argument to the function.

Code:

print(bin(4))
print(bin(9))

Output:

Python Built in Functions output 7

7. bool()

This function returns the Boolean value of an object.

Code:

print(bool(0))
print(bool(-4.5))
print(bool(None))
print(bool("False"))

Output:

Python Built in Functions output 8

8. bytearray()

This function returns a new array of bytes, i.e. a mutable sequence of integers from range 0 to 256.

Syntax –

bytearray(source,encoding,errors)

Note-

The values to function are optional.
If any non-ascii value is given to the function, it gives the error -TypeError: string argument without an encoding.

Code:

print(bytearray())
print(bytearray('Python','utf-8'))

Output:

Python Built in Functions output 9

9. compile()

It is used to generate a Python code object from a string or an AST object.

Following is the syntax for the function –

Compile(source,filename,mode,flags=0,dont_inherit=False,optimize=-1)

This function’s output is given as an argument to evaluate () and exec() function.

Code:

myCode = 'a = 7\nb=9\nresult=a*b\nprint("result =",result)'
codeObject = compile(myCode, 'resultstring', 'exec')
exec(codeObject)

Output:

10. list()

This function is used to convert an object to a list object.

Syntax –

list([iterable])

Here iterable refers to any sequence such as string, tuples, and iterable object or collection object such as a set or dictionary.

A mutable sequence of the list of elements is returned as an output of this function.

Code:

print(list()) #returns empty list
stringobj = 'PALINDROME'
print(list(stringobj))
tupleobj = ('a', 'e', 'i', 'o', 'u')
print(list(tupleobj))
listobj = ['1', '2', '3', 'o', '10u']
print(list(listobj))

Output:

Python Built in Functions output 11

11. len()

This function gives the length of the object as an output.

Syntax –

len([object])

Here objects must be either a sequence or collection.

Note- Interpreter throws an error in case it encounters no argument given to the function.

Code:

stringobj = 'PALINDROME'
print(len(stringobj))
tupleobj = ('a', 'e', 'i', 'o', 'u')
print(len(tupleobj))
listobj = ['1', '2', '3', 'o', '10u']
print(len(listobj))

Output:

Python Built in Functions output 12

12. max()

This function returns the largest number in the given iterable object or the maximum of two or more numbers given as arguments.

Syntax –

max(iterable) or max(num1,num2…)

Here iterable can be list, tuple, dictionary or any sequence or collection.

Code:

num = [11, 13, 12, 15, 14]
print('Maximum is:', max(num))

Output:

Python Built in Functions output 13

Note- In case no arguments are given to the function, then ValueError is thrown by the interpreter.

13. min()

This function returns the minimum value from the collection object or the values defined as arguments.

Syntax –

min([iterable])

Code:

print(min(2,5,3,1,0,99))
sampleObj = ['B','a','t','A']
print(min(sampleObj))

Output:

Python Built in Functions output 14

Note– In case no arguments are given to the function, then ValueError is thrown by the interpreter.

14. map()

This function helps in debugging as it provides the result after an operation is applied to each of the items in an iterable object.

Syntax –

map(fun,[Iterable])

where iterable can be a list, tuple, etc…

Code:

numList = (11, 21, 13, 41)
res = map(lambda x: x + x, numList)
print(list(res))

Output:

15. open()

After opening a particular file, this function returns a file object that helps to read or write into that file.

Syntax –

open(file, mode)

file -refers to the name with the complete path of the file to read or written into.\

mode- refers to the manner or the work we need to perform with the file. It can value like ‘r’,’a’,’x’ etc.

Code:

f = open("myFile.txt", "r")#read mode
print(f.read())

Output:

output 16

16. pow()

This function returns the value of the power of 1 number to another number.

Syntax –

pow(num1,num2)

where num1,num2 must be an integer, float or double.

Code:

print(pow(2,-3))
print(pow(2,4.5))
print(pow(3,0))

Output:

output 17

17. oct()

This function helps to generate the octal representation of a number.

Syntax –

oct(number)

where the number can be an integer, hexadecimal or binary number.

Code:

print("The octal representation of 32 is " + oct(32)) 
print("The octal representation of the"
    " ascii value of 'A' is " + oct(ord('A'))) 
print("The octal representation of the binary" " of 32 is " + oct(100000)) 
print("The octal representation of the binary"
                " of 23 is " + oct(0x17))

Output:

output 18

18. sorted()

This function has made the sorting of the numbers very easy.

Syntax –

sorted(iterable,key,reverse)

Here, iterable – refers to the list, tuple or any collection of objects that needs to be sorted.

Key – refers to the key on which the values must be sorted.

Reverse- this can be set to true to generate the list in descending order.

The output of this function is always a list.

Code:

sampleObj = (3,6,8,2,5,8,10)
print(sorted(sampleObj,reverse=True))
sampledict = {'a':'sss','g':'wq','t':2}
print(sorted(sampledict,key= len))

Output:

output 19

19. sum()

This function helps to sum the member of an iterable object.

Syntax –

sum([iterable],start)

Iterable refers to any iterable object list, tuple or dictionary or sequence of numbers.

Start – this marks the initialization of the sum result that needs to be added to the final result. It is an optional argument.

Code:

num = [2.5, 3, 4, -5]
numSum = sum(num)
print(numSum)
numSum = sum(num, 20)
print(numSum)

Output:

output 20

20. str()

This function helps to generate the printable representation of an Object.

Syntax –

str(object,encoding,errors)

where encoding and errors are optional.

Code:

print(str('A1323'))
b = bytes('pythön', encoding='utf-8')
print(str(b, encoding='ascii', errors='ignore'))
#errors='ignore' helps interpreter to ignore when it found a non Ascii character

Output:

output 21

21. type()

This function is used to print the type or the class the object passed as an argument belongs to. This function is used for debugging purposes.

Syntax –

type(Object)

It is also sometimes used to create a new object

Syntax-

type(name,bases,dict)

Code :

tupleObj=(3,4,6,7,9)
print(type(tupleObj))
new1 = type('New', (object, ),
dict(var1 ='LetsLearn', b = 2029))
print(type(new1))

Output :

output 22

22. callable()

This function returns True if the object passed as an argument is callable.

Syntax –

callable(Object)

Code:

def myFun(): 
    return 5
res = myFun 
print(callable(res)) #function is called to get this value
num1 = 15 * 5
print(callable(num1))#no function is called

Output:

output 23

23. input()

This function helps python to take input from the user. In python 2.7, Its name is raw_input() which has been changed to input(). Once enter, or esc is pressed system is resumed again.

Syntax –

input()

24. range()

This function returns the series of numbers between 2 specific numbers. This is very useful while dealing with a loop in a program as it helps to run a loop in a specific number of times.In python 3.6 – xrange() has been renamed as range().

Syntax –

range(start,stop,step)

Here, start- an Integer which marks the start of the series.

A stop-an integer that marks the last number of the series. The last number in the range is stop-1.

Step – an integer that lets to increment the loop with a specific number. By default, it is +1.

Code:

res = 1
for i in range(1, 10,2): 
       res = res * i 
print("multiplication of first 10 natural number :", res)

Output:

Note- Float numbers as an argument throws an error.

25. reversed()

This function returns an iterator to access the collection in reverse order.

Syntax–

reversed([sequence] or [collection])

Code:

tupleObj=(3,4,6,7,9)
for i in reversed(tupleObj): 
       print(i,end=' ')

Output:

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

Output:

b ' Hello World.'

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

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

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

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

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

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

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

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

Output:

Python float()

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

Python float() Example

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

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

Output:

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

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

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

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

Output:

Python len() Function

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

Python len() Function Example

Output:

Python list()

The python list() creates a list in python.

Python list() Example

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

Python hash() Function Example

Output:

21
461168601842737174

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

Output:

Welcome to Python 3.5's help utility!

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

Output:

325
1000.25

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

Output:

set()
{'1', '2'}
{'a', 'n', 'v', 't', 'j', 'p', 'i', 'o'}

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

Output:

0x1
0x156

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

Output:

139963782059696
139963805666864
139963781994504

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

Output:

102
Sohan
[email protected]

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

Output:

slice(None, 5, None)
slice(0, 5, 3)

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

Output:

['a', 'a', 'i', 'j', 'n', 'o', 'p', 't', 't', 'v']

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

Output:

256
32
82

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

Output:

Enter a value: 45
You entered: 45

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

Output:

integer values : 10 10 10

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

Python built-in functions with program