Lists Data Structure


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The Lists data structure is a versatile datatype in Python, which can be written as a list of comma separated values between square brackets.

Syntax

Here is the basic syntax for the structure −

List_name = [ elements ];

If you observe, the syntax is declared like arrays with the only difference that lists can include elements with different data types. The arrays include elements of the same data type. A list can contain a combination of strings, integers and objects. Lists can be used for the implementation of stacks and queues.

Lists are mutable. These can be changed as and when needed.

How to implement lists?

The following program shows the implementations of lists −

my_list = ['p','r','o','b','e']
# Output: p
print(my_list[0])

# Output: o
print(my_list[2])

# Output: e
print(my_list[4])

# Error! Only integer can be used for indexing
# my_list[4.0]

# Nested List
n_list = ["Happy", [2,0,1,5]]

# Nested indexing

# Output: a
print(n_list[0][1])

# Output: 5
print(n_list[1][3])

Output

The above program generates the following output −

List Data Structure

The built-in functions of Python lists are as follows −

  • Append()− It adds element to the end of list.

  • Extend()− It adds elements of the list to another list.

  • Insert()− It inserts an item to the defined index.

  • Remove()− It deletes the element from the specified list.

  • Reverse()− It reverses the elements in list.

  • sort() − It helps to sort elements in chronological order.



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