Friday, December 13, 2024

Most Important Things to Know About Python Functions

What is a function in Python?
The most important concept to understand is that in Python, functions are objects. This means a function can return another function and one function can take another function as an argument. We can also define a function within another function. Functions can also be assigned to a variable.
What are some of the built-in functions and methods in Python?
Here’s a list of valuable built-in Python functions and methods that shorten your code and improve its efficiency. Python’s reduce () function iterates over each item in a list, or any other iterable data type, and returns a single value.
Python and Machine Learning Square

Python Built-in Functions and Methods List with Examples

In this article , we will learn about the useful list of Python built-in functions and methods. Let’s understand what Python built-in functions are. Python built-in functions are those functions which are used to solve everyday programming tasks. These built-in functions are based on the functional programming model. We are going to discuss some of the best Python 3 built-in functions and methods in alphabetical order.

I will tell you about mostly used built-in methods in Python 3 along with the real-world examples. Now the question arises why do we need to check out this list, let me tell you why we need to have a look thoroughly in this useful Python 3 built-in functions list because these built-in functions will help us to solve common programming problems daily.

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Built-in functions in Python

1: Which of the following data types is immutable in Python?

2: What does the len() function do in Python?

3: Which keyword is used to define a function in Python?

4: What will print(type([1, 2, 3])) output?

5: Which statement is correct about Python indentation?

    Fill out the form to see the results

    Ever wondered how much you really know? It's time to put your brain to the test!

    Python 3 offers nearly around 68 built-in functions and methods to make python developers life easy. You can see below mostly used Python built-in methods with examples.

    Without further ado, Let’s begin checking out this useful Python 2 | 3 built-in methods cheat sheet.

    Python has a set of built-in functions.

    Function Description
    abs() Returns the absolute value of a number
    all() Returns True if all items in an iterable object are true
    any() Returns True if any item in an iterable object is true
    ascii() Returns a readable version of an object. Replaces none-ascii characters with escape character
    bin() Returns the binary version of a number
    bool() Returns the boolean value of the specified object
    bytearray() Returns an array of bytes
    bytes() Returns a bytes object
    callable() Returns True if the specified object is callable, otherwise False
    chr() Returns a character from the specified Unicode code.
    classmethod() Converts a method into a class method
    compile() Returns the specified source as an object, ready to be executed
    complex() Returns a complex number
    delattr() Deletes the specified attribute (property or method) from the specified object
    dict() Returns a dictionary (Array)
    dir() Returns a list of the specified object’s properties and methods
    divmod() Returns the quotient and the remainder when argument1 is divided by argument2
    enumerate() Takes a collection (e.g. a tuple) and returns it as an enumerate object
    eval() Evaluates and executes an expression
    exec() Executes the specified code (or object)
    filter() Use a filter function to exclude items in an iterable object
    float() Returns a floating point number
    format() Formats a specified value
    frozenset() Returns a frozenset object
    getattr() Returns the value of the specified attribute (property or method)
    globals() Returns the current global symbol table as a dictionary
    hasattr() Returns True if the specified object has the specified attribute (property/method)
    hash() Returns the hash value of a specified object
    help() Executes the built-in help system
    hex() Converts a number into a hexadecimal value
    id() Returns the id of an object
    input() Allowing user input
    int() Returns an integer number
    isinstance() Returns True if a specified object is an instance of a specified object
    issubclass() Returns True if a specified class is a subclass of a specified object
    iter() Returns an iterator object
    len() Returns the length of an object
    list() Returns a list
    locals() Returns an updated dictionary of the current local symbol table
    map() Returns the specified iterator with the specified function applied to each item
    max() Returns the largest item in an iterable
    memoryview() Returns a memory view object
    min() Returns the smallest item in an iterable
    next() Returns the next item in an iterable
    object() Returns a new object
    oct() Converts a number into an octal
    open() Opens a file and returns a file object
    ord() Convert an integer representing the Unicode of the specified character
    pow() Returns the value of x to the power of y
    print() Prints to the standard output device
    property() Gets, sets, deletes a property
    range() Returns a sequence of numbers, starting from 0 and increments by 1 (by default)
    repr() Returns a readable version of an object
    reversed() Returns a reversed iterator
    round() Rounds a numbers
    set() Returns a new set object
    setattr() Sets an attribute (property/method) of an object
    slice() Returns a slice object
    sorted() Returns a sorted list
    staticmethod() Converts a method into a static method
    str() Returns a string object
    sum() Sums the items of an iterator
    super() Returns an object that represents the parent class
    tuple() Returns a tuple
    type() Returns the type of an object
    vars() Returns the __dict__ property of an object
    zip() Returns an iterator, from two or more iterators

    Python has a set of built-in methods that you can use on strings.

    Note: All string methods returns new values. They do not change the original string.

    Method Description
    capitalize() Converts the first character to upper case
    casefold() Converts string into lower case
    center() Returns a centered string
    count() Returns the number of times a specified value occurs in a string
    encode() Returns an encoded version of the string
    endswith() Returns true if the string ends with the specified value
    expandtabs() Sets the tab size of the string
    find() Searches the string for a specified value and returns the position of where it was found
    format() Formats specified values in a string
    format_map() Formats specified values in a string
    index() Searches the string for a specified value and returns the position of where it was found
    isalnum() Returns True if all characters in the string are alphanumeric
    isalpha() Returns True if all characters in the string are in the alphabet
    isascii() Returns True if all characters in the string are ascii characters
    isdecimal() Returns True if all characters in the string are decimals
    isdigit() Returns True if all characters in the string are digits
    isidentifier() Returns True if the string is an identifier
    islower() Returns True if all characters in the string are lower case
    isnumeric() Returns True if all characters in the string are numeric
    isprintable() Returns True if all characters in the string are printable
    isspace() Returns True if all characters in the string are whitespaces
    istitle() Returns True if the string follows the rules of a title
    isupper() Returns True if all characters in the string are upper case
    join() Converts the elements of an iterable into a string
    ljust() Returns a left justified version of the string
    lower() Converts a string into lower case
    lstrip() Returns a left trim version of the string
    maketrans() Returns a translation table to be used in translations
    partition() Returns a tuple where the string is parted into three parts
    replace() Returns a string where a specified value is replaced with a specified value
    rfind() Searches the string for a specified value and returns the last position of where it was found
    rindex() Searches the string for a specified value and returns the last position of where it was found
    rjust() Returns a right justified version of the string
    rpartition() Returns a tuple where the string is parted into three parts
    rsplit() Splits the string at the specified separator, and returns a list
    rstrip() Returns a right trim version of the string
    split() Splits the string at the specified separator, and returns a list
    splitlines() Splits the string at line breaks and returns a list
    startswith() Returns true if the string starts with the specified value
    strip() Returns a trimmed version of the string
    swapcase() Swaps cases, lower case becomes upper case and vice versa
    title() Converts the first character of each word to upper case
    translate() Returns a translated string
    upper() Converts a string into upper case
    zfill() Fills the string with a specified number of 0 values at the beginning

    Here is the Python built-in functions list.

    abs( )
    The abs() function in Python get the positive (absolute) value of a numerical value.

    x = abs(-7.25)
    print(x)
    # output = 7.25
    all()
    The all() function in python checks if all the items of an iterable are true, else it returns False. The all() method also returns true if the iterable object is empty.

    list = [0, 2, 2]
    a = all(list)
    print(a)
    # output = False
    any()
    The any() function returns True if any item in an iterable is true, else it returns False. This method returns False if iterable is empty.

    tuple = (0, 1, False)
    a = any(tuple)
    print(a)
    # output = True
    ascii()
    The ascii() function returns a readable representation of an object (Strings, Tuples, Lists, etc.) It replaces non-ascii characters with escape characters.

    a = ascii("Mostly Såne")
    print(a)
    # output = 'Mostly S\xe5ne'
    bin()
    The bin() function converts an integer (number) to a binary string. It prefixed with 0b.

    a = bin(30)
    print(a)
    # output = 0b11110
    bool()
    The bool() function is very helpful in converting an object to a Boolean value. This function returns True, except the object is false, empty, 0 or none.

    a = bool(22)
    print(a)
    # output = True
    bytearray()
    The bytearray() function is used converts an object into bytearray objects.

    a = bytearray(22)
    print(a)
    # output = bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
    bytes()
    The bytes() function is used to convert objects into bytes object.

    a = bytes(22)
    print(a)
    # output: b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'

    callable()
    The callable() function gets True, and if the passed object is callable, else it returns false.

    def a():
      b = 5
    print(callable(a))
    # output = True
    chr()
    The chr() function gets the string character, which represents the defined unicode.

    a = chr(87)
    print(a)
    # output: W
    compile()
    The compile() function compiles the sources into a code.

    a = compile('print(45)', 'test', 'eval')
    exec(a)
    # output: 45
    complex()
    The complex() function forms a complex number | convert string | number to complex number.

    delattr()
    The delattr() function help us to remove the defined attribute from the declared object.

    class User:
      name = "Jaydon"
      mob = 182182922
      country = "Canada"
    delattr(Person, 'age')
    dict()
    The dict() function form a new dictionary.

    a = dict(name = "Jaydon", mob = 182182922, country = "Canada")
    print(a)
    # output = {'name': 'Jaydon', 'mob': 182182922, 'country': 'Canada'}
    dir()
    The dir() function gets all the properties and methods of the declared object, and It doesn’t get the values. It even returns the built-in properties which are default for all object.

    class User:
      name = "Jaydon"
      mob = 182182922
      country = "Canada"
    print(dir(User))
    # output = ['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'country', 'mob', 'name']
    divmod()
    Gets a tuple including the quotient and remainder when argument1 is divided by argument2.

    a = divmod(6, 2)
    print(a)
    # output = (3, 0)
    enumerate( )
    It gets an enumerate object for a sequence or iterator.

    a = ('john', 'ann', 'sia')
    b = enumerate(a)
    print(b)
    # output = <enumerate object at 0x7f802a241a20>
    eval()
    Allows a legal python program to run python code.

    a = 'print(28)'
    print(eval(a))
    exec()
    The exec() function executes dynamic python code.

    a = 'name = "John"\nprint(name)'
    print(exec(a))

    filter()
    The filter() function filters the sequence via a function, this function checks each elements in the iterator are true or not.
    score = [15, 10, 20, 17, 26, 42]
    def customFunc(a):
      if a < 20:
        return False
      else:
        return True
    players = filter(customFunc, score)
    for a in players:
      print(a)
    float( )
    The float() function transforms a numerical value to floating point.

    a = float(5)
    print(a)
    format()
    The format() function transforms the defined value into a specified format.

    frozenset()
    The frozenset() function gets the unchangeable object.

    list = ['Avengers', 'Wonder women', 'Batmen']
    a = frozenset(list)
    print(a)
    getattr()
    This function gets the value of the defined attribute from the particular object.

    class Student:
      name = "Ann"
      age = 28
      country = "USA"
    x = getattr(Student, 'age')
    print(x)
    # output = 28
    globals( )
    This function gets the dictionary from the current global symbol table.

    a = globals()
    print(a)
    hasattr()
    This function return True, if the defined object has the mentioned attribute, else it will return False.

    class Student:
      name = "Ann"
      age = 28
      country = "USA"
    x = hasattr(Student, 'age')
    print(x)
    # output = True
    hex()
    This method converts the numerical value into a hexadecimal value. The returned value comes with the 0x prefix.

    a = hex(225)
    print(a)
    # output = 0xe1
    id()
    This method gets a unique id for the defined object, Python provides a unique id to all the objects.

    a = ('oppo', 'iPhone', 'nokia')
    b = id(a)
    print(b)
    # output = 140390324530704
    input()
    A user can define the value using the input() function.

    print('What is your name:')
    a = input()
    print('Hi, ' + a)
    # output = Enter your name:
    # Digamber
    # Hi, Digamber
    int()
    This function transforms the mentioned value into a numerical value.

    a = int(2.9)
    print(a)
    # output = 2
    issubclass()
    Returns true, if the defined object is a subclass of the defined object, else it will return false.

    class speed:
      kmph = 136
    class car(speed):
      name = "BMW"
      speed = speed
    x = issubclass(car, speed)
    print(x)
    iter()
    This function gets an iterator object.

    x = iter(["john", "lisa", "maria", "ava"])
    print(next(x))
    print(next(x))
    print(next(x))
    print(next(x))
    # john
    # lisa
    # maria
    # ava
    len()
    This method returns the total number of elements in an object if an object is a string type, then the method will return the number of characters from the string.

    a = ["john", "lisa", "maria", "ava"]
    print(len(a))
    # 4

    list()
    The function generates a list object which is ordered and changeable.
    a = list(["john", "lisa", "maria", "ava"])
    print(len(a))
    # 4

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