Built-in Functions

What You'll Learn: In this tutorial, you'll explore various built-in functions in Python that can help you perform common tasks quickly and easily.

Key Built-in Functions

  1. abs() - Returns the absolute value of a number.

    • Example:

      python
      print(abs(-5))  # Output: 5
  2. all() - Returns True if all items in an iterable object are true.

    • Example:

      python
      print(all([True, True, False]))  # Output: False
  3. any() - Returns True if any item in an iterable object is true.

    • Example:

      python
      print(any([True, False, False]))  # Output: True
  4. ascii() - Returns a readable version of an object. Replaces non-ascii characters with escape characters.

    • Example:

      python
      print(ascii("Café"))  # Output: 'Caf\\xe9'
  5. bin() - Returns the binary version of a number.

    • Example:

      python
      print(bin(10))  # Output: '0b1010'
  6. bool() - Returns the boolean value of the specified object.

    • Example:

      python
      print(bool(0))  # Output: False
  7. bytearray() - Returns an array of bytes.

    • Example:

      python
      print(bytearray(5))  # Output: bytearray(b'\x00\x00\x00\x00\x00')
  8. bytes() - Returns a bytes object.

    • Example:

      python
      print(bytes(5))  # Output: b'\x00\x00\x00\x00\x00'
  9. callable() - Returns True if the specified object is callable, otherwise False.

    • Example:

      python
      print(callable(print))  # Output: True
  10. chr() - Returns a character from the specified Unicode code.

    • Example:

      python
      print(chr(97))  # Output: 'a'
  11. classmethod() - Converts a method into a class method.

    • Example:

      python
      class MyClass:
    @classmethod
    def my_class_method(cls):
        pass
  12. compile() - Returns the specified source as an object, ready to be executed.

    • Example:

      python
      code = "print('Hello, World!')"
compiled_code = compile(code, 'example', 'exec')
exec(compiled_code)
  13. complex() - Returns a complex number.

    • Example:

      python
      print(complex(1, 2))  # Output: (1+2j)
  14. delattr() - Deletes the specified attribute (property or method) from the specified object.

    • Example:

      python
      class MyClass:
    x = 5

delattr(MyClass, 'x')
  15. dict() - Returns a dictionary (Array).

    • Example:

      python
      print(dict(a=1, b=2))  # Output: {'a': 1, 'b': 2}
  16. dir() - Returns a list of the specified object's properties and methods.

    • Example:

      python
      print(dir(list))  # Output: List of list methods
  17. divmod() - Returns the quotient and the remainder when argument1 is divided by argument2.

    • Example:

      python
      print(divmod(10, 3))  # Output: (3, 1)
  18. enumerate() - Takes a collection (e.g., a tuple) and returns it as an enumerate object.

    • Example:

      python
      my_list = ['a', 'b', 'c']
for index, value in enumerate(my_list):
    print(index, value)
  19. eval() - Evaluates and executes an expression.

    • Example:

      python
      x = 1
print(eval('x + 1'))  # Output: 2
  20. exec() - Executes the specified code (or object).

    • Example:

      python
      code = "print('Hello, World!')"
exec(code)
  21. filter() - Use a filter function to exclude items in an iterable object.

    • Example:

      python
      my_list = [1, 2, 3, 4, 5]
filtered_list = list(filter(lambda x: x % 2 == 0, my_list))
print(filtered_list)  # Output: [2, 4]
  22. float() - Returns a floating point number.

    • Example:

      python
      print(float(5))  # Output: 5.0
  23. format() - Formats a specified value.

    • Example:

      python
      print(format(1234, ","))  # Output: '1,234'
  24. frozenset() - Returns a frozenset object.

    • Example:

      python
      my_set = frozenset([1, 2, 3])
print(my_set)  # Output: frozenset({1, 2, 3})
  25. getattr() - Returns the value of the specified attribute (property or method).

    • Example:

      python
      class MyClass:
    x = 5

print(getattr(MyClass, 'x'))  # Output: 5
  26. globals() - Returns the current global symbol table as a dictionary.

    • Example:

      python
      print(globals())  # Output: Dictionary of global variables
  27. hasattr() - Returns True if the specified object has the specified attribute (property/method).

    • Example:

      python
      class MyClass:
    x = 5

print(hasattr(MyClass, 'x'))  # Output: True
  28. hash() - Returns the hash value of a specified object.

    • Example:

      python
      print(hash("hello"))  # Output: Hash value
  29. help() - Executes the built-in help system.

    • Example:

      python
      help(print)  # Output: Documentation for the print function
  30. hex() - Converts a number into a hexadecimal value.

    • Example:

      python
      print(hex(255))  # Output: '0xff'
  31. id() - Returns the id of an object.

    • Example:

      python
      x = 5
print(id(x))  # Output: Object ID
  32. input() - Allows user input.

    • Example:

      python
      name = input("Enter your name: ")
print(name)
  33. int() - Returns an integer number.

    • Example:

      python
      print(int("10"))  # Output: 10
  34. isinstance() - Returns True if a specified object is an instance of a specified object.

    • Example:

      python
      print(isinstance(5, int))  # Output: True
  35. issubclass() - Returns True if a specified class is a subclass of a specified object.

    • Example:

      python
      class A:
    pass

class B(A):
    pass

print(issubclass(B, A))  # Output: True
  36. iter() - Returns an iterator object.

    • Example:

      python
      my_list = [1, 2, 3]
my_iter = iter(my_list)
print(next(my_iter))  # Output: 1
  37. len() - Returns the length of an object.

    • Example:

      python
      print(len("hello"))  # Output: 5
  38. list() - Returns a list.

    • Example:

      python
      print(list((1, 2, 3)))  # Output: [1, 2, 3]
  39. locals() - Returns an updated dictionary of the current local symbol table.

    • Example:

      python
      def my_function():
    local_var = 10
    print(locals())  # Output: Dictionary of local variables

my_function()
  40. map() - Returns the specified iterator with the specified function applied to each item.

    • Example:

      python
      def add_one(x):
    return x + 1

my_list = [1, 2, 3]
result = map(add_one, my_list)
print(list(result))  # Output: [2, 3, 4]
  41. max() - Returns the largest item in an iterable.

    • Example:

      python
      print(max([1, 2, 3, 4]))  # Output: 4
  42. memoryview() - Returns a memory view object.

    • Example:

      python
      my_bytes = b"Hello"
mv = memoryview(my_bytes)
print(mv[1])  # Output: 101
  43. min() - Returns the smallest item in an iterable.

    • Example:

      python
      print(min([1, 2, 3, 4]))  # Output: 1
  44. next() - Returns the next item in an iterable.

    • Example:

      python
      my_iter = iter([1, 2, 3])
print(next(my_iter))  # Output: 1
  45. object() - Returns a new object.

    • Example:

      python
      obj = object()
print(type(obj))  # Output: <class 'object'>
  46. oct() - Converts a number into an octal.

    • Example:

      python
      print(oct(8))  # Output: '0o10'
  47. open() - Opens a file and returns a file object.

    • Example:

      python
      file = open('example.txt', 'r')
content = file.read()
file.close()
  48. ord() - Convert an integer representing the Unicode of the specified character.

    • Example:

      python
      print(ord('a'))  # Output: 97
  49. pow() - Returns the value of x to the power of y.

    • Example:

      python
      print(pow(2, 3))  # Output: 8
  50. print() - Prints to the standard output device.

    • Example:

      python
      print("Hello, World!")  # Output: Hello, World!
  51. property() - Gets, sets, deletes a property.

    • Example:

      python
      class MyClass:
    def __init__(self):
        self._x = None

    def get_x(self):
        return self._x

    def set_x(self, value):
        self._x = value

    def del_x(self):
        del self._x

    x = property(get_x, set_x, del_x)

obj = MyClass()
obj.x = 10
print(obj.x)  # Output: 10
  52. range() - Returns a sequence of numbers, starting from 0 and increments by 1 (by default).

    • Example:

      python
      print(list(range(5)))  # Output: [0, 1, 2, 3, 4]
  53. repr() - Returns a readable version of an object.

    • Example:

      python
      print(repr("Hello, World!"))  # Output: 'Hello, World!'
  54. reversed() - Returns a reversed iterator.

    • Example:

      python
      print(list(reversed([1, 2, 3])))  # Output: [3, 2, 1]
  55. round() - Rounds a number.

    • Example:

      python
      print(round(5.678, 2))  # Output: 5.68
  56. set() - Returns a new set object.

    • Example:

      python
      my_set = set([1, 2, 3])
print(my_set)  # Output: {1, 2, 3}
  57. setattr() - Sets an attribute (property/method) of an object.

    • Example:

      python
      class MyClass:
    x = 5

setattr(MyClass, 'x', 10)
print(MyClass.x)  # Output: 10
  58. slice() - Returns a slice object.

    • Example:

      python
      my_slice = slice(1, 4)
print([1, 2, 3, 4, 5][my_slice])  # Output: [2, 3, 4]
  59. sorted() - Returns a sorted list.

    • Example:

      python
      print(sorted([3, 1, 4, 1, 5]))  # Output: [1, 1, 3, 4, 5]
  60. staticmethod() - Converts a method into a static method.

    • Example:

      python
      class MyClass:
    @staticmethod
    def my_static_method():
        print("Static method called")

MyClass.my_static_method()
  61. str() - Returns a string object.

    • Example:

      python
      print(str(123))  # Output: '123'
  62. sum() - Sums the items of an iterator.

    • Example:

      python
      print(sum([1, 2, 3]))  # Output: 6
  63. super() - Returns an object that represents the parent class.

    • Example:

      python
      class A:
    def __init__(self):
        print("A's init called")

class B(A):
    def __init__(self):
        super().__init__()
        print("B's init called")

obj = B()
  64. tuple() - Returns a tuple.

    • Example:

      python
      print(tuple([1, 2, 3]))  # Output: (1, 2, 3)
  65. type() - Returns the type of an object.

    • Example:

      python
      print(type(123))  # Output: <class 'int'>
  66. vars() - Returns the __dict__ property of an object.

    • Example:

      python
      class MyClass:
    x = 5

obj = MyClass()
print(vars(obj))  # Output: {}
  67. zip() - Returns an iterator, from two or more iterators.

    • Example:

      python
      list1 = [1, 2, 3]
list2 = ['a', 'b', 'c']
print(list(zip(list1, list2)))  # Output: [(1, 'a'), (2, 'b'), (3, 'c')]

Try It Yourself: Fun Exercises

  1. Explore Number Functions:
    • Use abs(), bin(), and pow() to experiment with different numbers and see how they work.
  2. Work with Booleans:
    • Use all() and any() to test different lists of boolean values.
  3. Character and Byte Manipulations:
    • Use chr() and bytes() to understand how characters and byte objects are handled in Python.

Summary:

In this Python tutorial, we explored various built-in functions that are essential for performing common tasks. These functions make it easier to write efficient and effective code. Keep experimenting and have fun with Python!