Python Built-In Functions with Syntax and Examples

We have talked about Functions in Python. In that tutorial of Python Functions, we discussed user-defined functions in Python. But that isn’t all, a list of Python built-in functions that we can toy around with.

In this tutorial on Built-in functions in Python, we will see each of those; we have 67 of those in Python 3.6 with their Python Syntax and examples.

So, let’s start Python Built-In Functions.

What are Python Built-In Functions?

Python ships with many ready-made helpers called built-in functions. You do not import them; they sit in memory the moment the interpreter starts. Names like len, sum, and print pop up in almost every script because they solve everyday chores quickly.

When you learn what each built-in function does, your code becomes shorter and more expressive. A one-line sum(numbers) tells more than a loop that adds by hand. Mastering this toolbox is the first step toward writing Pythonic programs that rank high in clarity and performance.

1. abs() in python

The abs() in python is one of the most popular Python built-in functions, which returns the absolute value of a number.

A negative value’s absolute is that value is positive.

>>> abs(-7)

Output

>>> abs(7)

Output

>>> abs(0)

2. all() in python

The all() function in Python takes a container as an argument. This built-in function returns True if all values in a Python iterable have a Boolean value of True.

An empty value has a Boolean value of False.

>>> all({'*','',''})

Output

>>> all([' ',' ',' '])

Output

3. any() in python

Like all(), it takes one argument and returns True if, even one value in the iterable has a Boolean value of True.

>>> any((1,0,0))

Output

>>> any((0,0,0))

Output

4.  ascii() in python

Python built-in functions must return a printable representation of a Python object (like a string or a Python list).

Let’s take a Romanian character.

>>> ascii('ș')

Output

Since this was a non-ASCII character in Python, the interpreter added a backslash (\) and escaped it using another backslash.

>>> ascii('ușor')

Output

Let’s apply it to a list.

>>> ascii(['s','ș'])

Output

5. bin() in python

The bin() function in Python converts an integer to a binary string. We have seen this and other functions in our article on Python Numbers.

>>> bin(7)

Output

We can’t apply it on floats, though.

>>> bin(7.0)

Output

6. bool() in python

The bool() function in Python converts a value to a Boolean.

>>> bool(0.5)

Output

>>> bool('')

Output

>>> bool(True)

Output

7. bytearray() in python

The bytearray() function returns a Python array of a given byte size.

>>> a=bytearray(4)
>>> a

Output

>>> a.append(1)
>>> a

Output

>>> a[0]=1
>>> a

Output

>>> a[0]

Output

Let’s do this on a list.

>>> bytearray([1,2,3,4])

Output

8. bytes() in Python

The bytes() function in Python returns an immutable bytes object.

>>> bytes(5)

Output

>>> bytes([1,2,3,4,5])

Output

>>> bytes('hello','utf-8')

Output

Both bytes() and bytearray() deal with raw data, but bytearray() is mutable, while bytes() is immutable.

>>> a=bytes([1,2,3,4,5])
>>> a

Output

>>> a[4]=

Output

Let’s try this on bytearray().

>>> a=bytearray([1,2,3,4,5])
>>> a

Output

>>> a[4]=3
>>> a

Output

9. callable() in Python

The callable() function in Python tells us if an object can be called.

>>> callable([1,2,3])

Output

>>> callable(callable)

Output

>>> callable(False)

Output

>>> callable(list)

Output

A function is callable; a list is not. Even the callable() Python built-in function is callable.

10. chr() in Python

chr() Built-in function returns the character in Python for an ASCII value.

>>> chr(65)

Output

>>> chr(97)

Output

>>> chr(9)

Output

>>> chr(48)

Output

11. classmethod() in Python

The classmethod() function in Python returns a class method for a given method.

>>> class fruit:
                def sayhi(self):
                                print("Hi, I'm a fruit") 
       
>>> fruit.sayhi=classmethod(fruit.sayhi)
>>> fruit.sayhi()

Output

When we pass the method sayhi() as an argument to classmethod(), it converts it into a Python class method that belongs to the class.

Then, we call it like we would call any static method in Python without an object.

12. compile() in Python

The compile() function in Python returns a Python code object. We use Python in built function to convert a string code into object code.

>>> exec(compile('a=5\nb=7\nprint(a+b)','','exec'))

Output

Here, ‘exec’ is the mode. The parameter before that is the filename for the file form which the code is read.

Finally, we execute it using exec().

13. complex() in Python

The complex() function in Python creates a complex number. We have seen this in our article on Python Numbers.

>>> complex(3)

Output

>>> complex(3.5)

Output

>>> complex(3+5j)

Output

14. delattr() in Python

The delattr() function in Python takes two arguments- a class, and an attribute in it. It deletes the attribute.

>>> class fruit:
                size=7  
         
>>> orange=fruit()
>>> orange.size

Output

>>> delattr(fruit,'size')
>>> orange.size

Output

15. dict() in Python

The dict() function in Python, as we have seen it, creates a Python dictionary.

>>> dict()

Output

>>> dict([(1,2),(3,4)])

Output

This was about dict() Python built-in function

16. dir() in Python

The dir() function in Python returns an object’s attributes.

>>> class fruit:
                size=7
                shape='round'
>>> orange=fruit()
>>> dir(orange)

Output

17. divmod() in Python

divmod() is a built-in function, takes two parameters, and returns a tuple of their quotient and remainder.

In other words, it returns the floor division and the modulus of the two numbers.

>>> divmod(3,7)

Output

>>> divmod(7,3)

Output

If you encounter any doubt in Python Built-in Function, Please Comment.

18. enumerate() in Python

This Python built-in function returns an enumerate object. In other words, it adds a counter to the iterable.

>>> for i in enumerate(['a','b','c']):
                print(i)

Output

19. eval() in Python

The eval() Function in Python takes a string as an argument, which is parsed as an expression.

>>> x=7
>>> eval('x+7')

Output

>>> eval('x+(x%2)')

Output

20. exec() in Python

The exec() function runs Python code dynamically.

>>> exec('a=2;b=3;print(a+b)')

Output

>>> exec(input("Enter your program"))

Output

21. filter() in Python

Like we’ve seen in python Lambda Expressios, filter() filters out the items for which the condition is True.

>>> list(filter(lambda x:x%2==0,[1,2,0,False]))

Output

22. float() in Python

This Python built-in function converts an int or a compatible value into a float.

>>> float(2)

Output

>>> float('3')

Output

>>> float('3s')

Output

>>> float(False)

Output

>>> float(4.7)

Output

23. format() in Python

We have seen this Python built-in function, one in our lesson on Python Strings.

>>> a,b=2,3
>>> print("a={0} and b={1}".format(a,b))

Output

>>> print("a={a} and b={b}".format(a=3,b=4))

Output

24. frozenset() in Python

frozenset() returns an immutable frozenset object.

>>> frozenset((3,2,4))

Output

25. getattr() in Python

getattr() returns the value of an object’s attribute.

>>> getattr(orange,'size')

Output

26. globals() in Python

This Python built-in functions, returns a dictionary of the current global symbol table.

>>> globals()

Output

27. hasattr() in Python

Like delattr() and getattr(), hasattr() Python built-in functions, returns True if the object has that attribute.

>>> hasattr(orange,'size')

Output

>>> hasattr(orange,'shape')

Output

>>> hasattr(orange,'color')

Output

28. hash() in Python

hash() function returns the hash value of an object. And in Python, everything is an object.

>>> hash(orange)

Output

>>> hash(orange)

Output

>>> hash(True)

Output

>>> hash(0)

Output

>>> hash(3.7)

Output

>>> hash(hash)

Output

This was all about hash() Python built-in function

29. help() in Python

To get details about any module, keyword, symbol, or topic, we use the help() function.

>>> help()

Welcome to Python 3.6's help utility!

If this is your first time using Python, you should definitely check out the tutorial on the Internet at http://docs.python.org/3.6/tutorial/.

Enter the name of any module, keyword, or topic to get help on writing Python programs and using Python modules.  To quit this help utility and return to the interpreter, just type "quit".

To get a list of available modules, keywords, symbols, or topics, type "modules", "keywords", "symbols", or "topics".  Each module also comes with a one-line summary of what it does; to list the modules whose name or summary contain a given string such as "spam", type "modules spam".

help> map
Help on class map in module builtins:
class map(object)
|  map(func, *iterables) --> map object 
| 
|  Make an iterator that computes the function using arguments from
|  each of the iterables.  Stops when the shortest iterable is exhausted.
|
|  Methods defined here:
|
|  __getattribute__(self, name, /)
|      Return getattr(self, name).
|
|  __iter__(self, /)
|      Implement iter(self).
|
|  __new__(*args, **kwargs) from builtins.type
|      Create and return a new object.  See help(type) for accurate signature.
|
|  __next__(self, /)
|      Implement next(self).
|
|  __reduce__(...)
|      Return state information for pickling.
help> You are now leaving help and returning to the Python interpreter.
If you want to ask for help on a particular object directly from the
interpreter, you can type "help(object)".  Executing "help('string')"
has the same effect as typing a particular string at the help> prompt.
>>>

30. hex() in Python

Hex() Python built-in functions, converts an integer to hexadecimal.

>>> hex(16)

Output

>>> hex(False)

Output

31. id() Function in Python

id() returns an object’s identity.

>>> id(orange)

Output

>>> id({1,2,3})==id({1,3,2})

Output

32.  input() in Python

Input() Python built-in functions, reads and returns a line of string.

>>> input("Enter a number")

Output

Note that this returns the input as a string. If we want to take 7 as an integer, we need to apply the int() function to it.

>>> int(input("Enter a number"))

Output

33. int() in Python

int() converts a value to an integer.

>>> int('7')

Output

34. isinstance() V

We have seen this one in previous lessons. isinstance() takes a variable and a class as arguments.

Then, it returns True if the variable belongs to the class. Otherwise, it returns False.

>>> isinstance(0,str)

Output

>>> isinstance(orange,fruit)

Output

35. issubclass() in Python

This Python built-in function takes two arguments- two Python classes. If the first class is a subclass of the second, it returns True.

Otherwise, it returns False.

>>> issubclass(fruit,fruit)

Output

>>> class fruit:
           pass
>>> class citrus(fruit):
           pass

>>> issubclass(fruit,citrus)

Output

36. iter() in Python

Iter() is built-in functions returns a Python iterator for an object.

>>> for i in iter([1,2,3]):
            print(i)

Output

37. len() in Python

We’ve seen len() so many times by now. It returns the length of an object.

>>> len({1,2,2,3})

Output

Here, we get 3 instead of 4, because the set takes the value ‘2’ only once.

38. list() in Python

list() creates a list from a sequence of values.

>>> list({1,3,2,2})

Output

39. locals() in Python

This function returns a dictionary of the current local symbol table.

>>> locals()

Output

40. map() in Python

Like filter(), map(), Python built-in functions, take a function and apply it to an iterable. It maps True or False values on each item in the iterable.

>>> list(map(lambda x:x%2==0,[1,2,3,4,5]))

Output

41. max() in Python

A no-brainer, max() returns the item, in a sequence, with the highest value of all.

>>> max(2,3,4)

Output

>>> max([3,5,4])

Output

>>> max('hello','Hello')

Output

42. memoryview() in Python

memoryview() shows us the memory view of an argument.

>>> a=bytes(4)
>>> memoryview(a)

Output

>>> for i in memoryview(a): 
         print(i)

43. min() in Python

min() returns the lowest value in a sequence.

>>> min(3,5,1)

Output

>>> min(True,False)

Output

44. next() in Python

This Python Built In function returns the next element from the iterator.

>>> myIterator=iter([1,2,3,4,5])
>>> next(myIterator)

Output

>>> next(myIterator)

Output

>>> next(myIterator)

Output

>>> next(myIterator)

Output

>>> next(myIterator)

Output

Now that we’ve traversed all items, when we call next(), it raises StopIteration.

>>> next(myIterator)

Output

45. object() in Python

Object() Python built-in functions, creates a featureless object.

>>> o=object()
>>> type(o)

Output

>>> dir(o)

Output

Here, the function type() tells us that it’s an object. dir() tells us the object’s attributes. But since this does not have the __dict__ attribute, we can’t assign to arbitrary attributes.

46. oct() in Python

oct() converts an integer to its octal representation.

>>> oct(7)

Output

>>> oct(8)

Output

>>> oct(True)

Output

47. open() in Python

open() lets us open a file. Let’s change the current working directory to Desktop.

>>> import os
>>> os.chdir('C:\\Users\\lifei\\Desktop')

Now, we open the file ‘topics.txt’.

>>> f=open('topics.txt')
>>> f

Output

>>> type(f)

Output

To read from the file, we use the read() method.

>>> print(f.read())
DBMS mappings
projection
union
rdbms vs dbms
doget dopost
how to add maps
OOT
SQL queries
Join
Pattern programs

Output

48. ord() in Python

The function ord() returns an integer that represents the Unicode point for a given Unicode character.

>>> ord('A')

Output

>>> ord('9')

Output

This is complementary to chr().

>>> chr(65)

Output

49. pow() in Python

pow() takes two arguments- say, x and y. It then returns the value of x to the power of y.

>>> pow(3,4)

Output

>>> pow(7,0)

Output

>>> pow(7,-1)

Output

>>> pow(7,-2)

Output

50. print() in Python

We don’t think we need to explain this anymore. We’ve been seeing this function since the beginning of this article.

>>> print("Okay, next function, please!")

Output

51. property() in Python

The function property() returns a property attribute. Alternatively, we can use the syntactic sugar @property.

We will learn this in detail in our tutorial on Python Property.

52. range() in Python

We’ve taken a whole tutorial on this. Read up range() in Python.

>>> for i in range(7,2,-2):
         print(i)

Output

53. repr() in Python

repr() returns a representable string of an object.

>>> repr("Hello")

Output

>>> repr(7)

Output

>>> repr(False)

Output

54. reversed() in Python

This function reverses the contents of an iterable and returns an iterator object.

>>> a=reversed([3,2,1])
>>> a

Output

>>> for i in a:
print(i)

Output

>>> type(a)

Output

55. round() in Python

round() rounds off a float to the given number of digits (given by the second argument).

>>> round(3.777,2)

Output

>>> round(3.7,3)

Output

>>> round(3.7,-1)

Output

>>> round(377.77,-1)

Output

The rounding factor can be negative.

56. set() in Python

Of course, set() returns a set of the items passed to it.

>>> set([2,2,3,1])

Output

Remember, a set cannot have duplicate values, and isn’t indexed, but is ordered. Read on Sets and Booleans for the same.

57. setattr() in Python

Like getattr(), setattr() sets an attribute’s value for an object.

>>> orange.size

Output

>>> orange.size=8
>>> orange.size

Output

58. slice() in Python

slice() returns a slice object that represents the set of indices specified by range(start, stop, step).

>>> slice(2,7,2)

Output

We can use this to iterate on an iterable like a string in python.

>>> 'Python'[slice(1,5,2)]

Output

59.  sorted() in Python

Like we’ve seen before, sorted() prints out a sorted version of an iterable. It does not, however, alter the iterable.

>>> sorted('Python')

Output

>>> sorted([1,3,2])

Output

60. staticmethod() in Python

staticmethod() creates a static method from a function. A static method is bound to a class rather than to an object.

But it can be called on the class or on an object.

>>> class fruit:
            def sayhi():
                          print("Hi")
>>> fruit.sayhi=staticmethod(fruit.sayhi)
>>> fruit.sayhi()

Output

You can also use the syntactic sugar @staticmethod for this.

>>> class fruit:
            @staticmethod
             def sayhi():
                     print("Hi")
>>> fruit.sayhi()

Output

61. str() in Python

str() takes an argument and returns the string equivalent of it.

>>> str('Hello')

Output

>>> str(7)

Output

>>> str(8.7)

Output

>>> str(False)

Output

>>> str([1,2,3])

Output

62. sum() in Python

The function sum() takes an iterable as an argument, and returns the sum of all values.

>>> sum([3,4,5],3)

Output

63. super() in Python

super() returns a proxy object to let you refer to the parent class.

>>> class person:
           def __init__(self):
               print("A person")
>>> class student(person):
            def __init__(self):
                super().__init__()
                print("A student")
>>> Avery=student()

Output

64. tuple() in Python

As we’ve seen in our tutorial on Python Tuples, the function tuple() lets us create a tuple.

>>> tuple([1,3,2])

Output

>>> tuple({1:'a',2:'b'})

Output

65. type() in Python

We have been seeing the type() function to check the type of object we’re dealing with.

>>> type({})

Output

>>> type(set())

Output

>>> type(())

Output

>>> type((1))

Output

>>> type((1,))

Output

66. vars() in Python

vars() function returns the __dict__ attribute of a class.

>>> vars(fruit)

Output

67. zip() in Python

zip() returns us an iterator of tuples.

>>> set(zip([1,2,3],['a','b','c']))

Output

>>> set(zip([1,2],[3,4,5]))

Output

>>> a=zip([1,2,3],['a','b','c'])

To unzip this, we write the following code.

>>> x,y,z=a
>>> x

Output

>>> y

Output

>>> z

Output

Isn’t this just like tuple unpacking? So, this was all about Python Built-in Functions. Hope you like our explanation.

Python Interview Question on Built-in Functions

1. What are the built-in functions in Python?

2. How many built-in functions does Python have?

3. Give an example of a built-in function in the Python library.

4. What are the built-in functions in Python?

5. How do you find the built-in functions in Python?

Conclusion

Phew, was that too much for once? It may be overwhelming at once, but as you will get using these python Built-in functions, you will get used to them.