Programming Tutorials

python list

By: Ashley J in Python Tutorials on 2017-09-27  

In Python, a list is a mutable, ordered sequence of items. Here are some of the commonly used operations that can be performed on lists:

1. Creating a list: To create a list, we can use square brackets [] or the list() constructor.

   Example:

   my_list = [1, 2, 3, 4, 5]
   my_list = list(range(1, 6))
   

2. Accessing list elements: We can access the elements of a list using their index.

   Example:

   my_list = [1, 2, 3, 4, 5]
   print(my_list[0])    # Output: 1
   print(my_list[-1])   # Output: 5
   

3. Modifying list elements: We can modify the elements of a list using their index.

   Example:

   my_list = [1, 2, 3, 4, 5]
   my_list[0] = 6
   print(my_list)    # Output: [6, 2, 3, 4, 5]
   

4. Adding elements to a list: We can add elements to a list using the append() method or the + operator.

   Example:

   my_list = [1, 2, 3]
   my_list.append(4)
   print(my_list)    # Output: [1, 2, 3, 4]
   
   my_list = [1, 2, 3]
   my_list = my_list + [4]
   print(my_list)    # Output: [1, 2, 3, 4]
   

5. Removing elements from a list: We can remove elements from a list using the remove() method or the del keyword.

   Example:

   my_list = [1, 2, 3, 4, 5]
   my_list.remove(3)
   print(my_list)    # Output: [1, 2, 4, 5]
   
   my_list = [1, 2, 3, 4, 5]
   del my_list[2]
   print(my_list)    # Output: [1, 2, 4, 5]
   

6. Slicing a list: We can extract a subset of a list using slicing.

   Example:

   my_list = [1, 2, 3, 4, 5]
   print(my_list[1:3])    # Output: [2, 3]
   

7. Finding the length of a list: We can find the number of elements in a list using the len() function.

   Example:

   my_list = [1, 2, 3, 4, 5]
   print(len(my_list))    # Output: 5
   

8. Sorting a list: We can sort a list using the sort() method.

   Example:

   my_list = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5]
   my_list.sort()
   print(my_list)    # Output: [1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9]