Collection In Python-

Python is providing a pre-defined library called collections.

How Many Types Of Collections In Python-

  • 1) List
  • 2) Tuple
  • 3) Set
  • 4) Dict

1) List –

  • – Can store heterogeneous elements together.
  • – Maintain insertion order.
  • – Can store duplicate elements as well.
  • – Can access the elements by indexing and by slicing.

Ex –

l = [10,20,30,40,50]

list_data = [1, 2, 3]
print(list_data)

list_data = [1, 2, 'Python', 3]
print(list_data)
##### Indexing #####
print(list_data[0])
print(list_data[1])
##### Slicing #####
print(list_data[-2])
print(list_data[-1])
print(list_data[1:3])
print(list_data[1:])
print(list_data[:3])

Output-
	[1, 2, 3]
	[1, 2, 'Python', 3]
	1
	2
	Python
	3
	[2, 'Python']
	[2, 'Python', 3]
	[1, 2, 'Python']

Predefined/Existing Methods-

    • 1) Index() –

      Index is used to return the index value of a particular element.

    • Return only first index of occurrence in case of duplicate elements.

 

    • 2) Count-

      Used to count the no. of occurrence of any particular element.

 

    • 3) Append –

      Used to add the elements at the last index.

 

    • 4) Insert(Index_no, Val) –

      Used to add the element at a particular location.

 

    • 5) Pop()-

      Used to remove the elements from last first (On the basis of LIFO(Last in first out)).

 

    • 6) Pop(Index_no)-

      Used to remove the elements from particular index.

 

    • 7) Remove(Element) –

      Used to remove a particular element.

 

    • 8) Clear() –

      Used to remove all the elements from list.

 

    • 9) Sort() –

      Used to sort the element.

 

    • 10) Extend() –

      Used to add more then one list into the another.

 

    • – Python supports dynamic data type concept. Hence every element act like as an object.
    • – int, float and string are immutable object in python.
    • – list can also contain tuples as an element and vice versa is also possible.

 

    • Qsn:

      Why all data types are immutable in python?

    • Ans:

      because we don’t have primitive data type concept in python.

 

  • Notes-

    list is mutable(Changeable) but list element can be either mutable(Changeable) or immutable(unchangeable).

  • l = [10,20, [30,40]]

Ex-

list_data = [1 ,2,(3 ,4 ), 5, [6 ,7]]
print(list_data)

Output-
	[1, 2, (3, 4), 5, [6, 7]]
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