Python List Operations

An article about Python list operations could cover the different ways you can work with lists in Python, including creating, accessing, modifying, adding, removing, and updating elements from lists. It could explain the basic syntax for these operations, and provide examples of how to use them in practical applications.

What is Python List?

A list is a collection of ordered and mutable elements enclosed in square brackets []. It can contain any type of object, including numbers, strings, other lists, tuples, and dictionaries. In Python, Lists are one of the most commonly used data structures.

Example for python list:

list = ["Student", "Teacher", "Parent"]
print(list)

Output

['Student', 'Teacher', 'Parent']

Explanation for python list
By using square brackets [] we print our list as output.

Python List Operations Types

There are many different types of operations that you can perform on Python lists, including:

1. Access Elements of a List

A Python lists Operations entries can be accessed using the indexes [0], [1], etc. An element in a list with an index of n has an index of n-1 since the index begins at 0. Negative indexing refers to beginning at the end. The numbers -1 and -2 denote the last and second-to-last items, respectively. By defining the beginning and ending points of the range, you can specify a range of indexes. A new list containing the items you requested will be the return value when you specify a range.

Example for Access element of a list

list=["Student", "Teacher", "Parent", 1, 5, 6, 8]
print(list[0])
print(list[-1])  
print(list[2:5])

Output

Student
Parent
['Parent', 1, 5]

Explanation for Access element of a list
Using index[0] we accessed the first element of the list. Using index[-1] we accessed the last element in the list. Using list[begin: end] we accessed the second, third, and fourth elements in list

2. Add Elements to a List

The append and insert functions in Python allow for the addition (or appending) of elements to lists. We can add elements to a list at any location by using the insert function. This function requires two arguments: The element’s desired insertion index and the addition of the element. Use the insert() method to add a list item at a specific index. Use the extend() method to add elements from another list to the one that is now displayed. Any iterable object may be added using the extend() method; lists are not required to be appended (tuples, sets, dictionaries, etc.).

Example of adding elements to a list

list = ["Student", "Teacher", "Parent"]
list.append("Friend")
print(list) list.insert(1, "Friend")
print(list) 
add = [1,2,3]
list.extend(add)
print(list) 
tuple = ("Friend", 2, 3)
list.extend(tuple)
print(list) 

Output

['Student', 'Teacher', 'Parent', 'Friend']
['Student', 'Teacher', 'Parent', 1, 2, 3]
['Student', 'Teacher', 'parent', 'Friend', 2, 3]

Explanation of adding elements to a list
Adding elements to the end of a list is done with the append function. At the specified index, the insert() function inserts an item. By using the keyword ‘extend’ the list is extended with add list and prints the output. By using the keyword ‘extend’ we extended the list with a tuple.

3. Lists Sorting

The list’s elements can be sorted either ascendingly or descendingly.

Example for Lists Sorting

list = ["Student", "Teacher", "Parent", "Friend"]
list.sort()
print(list)

Output

['Friend', 'Parent', 'Student', 'Teacher']

Explanation for Lists sorting
List objects include a function called sort() that, sorts the list alphabetically in ascending order

4. Update Elements of a List

Lists can be modified, therefore by utilizing the element’s index, we can update the list’s elements.

Example for Update elements of a list

list = [1, 'Apple', 'Subject', 75, True]
list[2] = 'Carrot'
print(list) 

Output

[1, 'Apple', 'Carrot', 75, True]

Explanation for update elements of a list
The element is updated in the list by using the index of an element in the list.

5. Remove Elements from a List

Using the remove function, we can easily delete a list element.

Example for Remove elements from a list

list = ['School', 'College', 'Music', 'Games']
list.remove('Music')
print(list) 

Output

['School', 'College', 'Games']

Explanation for Remove elements from a list
By using the ‘remove’ keyword we removed the element in the list.

6. List Elements should be Inserted

The pop function removes or pops out the last element from a list and outputs the remaining elements.

Example for List elements should be inserted

list = [1, 2, 3, 4]
list.pop()
print(list) 

Output

[1, 2, 3]

Explanation for List elements should be inserted
By using ‘pop’ keyword the last element is removed and prints the list.

7. Length/Number of Elements in a List

The length function can be used to determine the total number of elements in a list.

Example for length of elements in a list

list = [1, 2, 5, 8, 9]
print(len(list)) 

Output

5

Explanation for length of elements in a list
By using the keyword ‘len’ it prints the length of the list.

8. Maximum Element within a List

Using the very simple max function, we can quickly find the maximum of the numbers in a list.The Max function only works on homogeneous lists, that is, lists with elements of the same data type.

Example for Maximum element within a list

list = [1, 2, 5, 6]
max(list)

Output

6

Explanation for Maximum element within a list
By using the keyword ‘max’ it prints the maximum element within a list.

9. Concatenate Lists

Using the ‘+’ operator, we can easily concatenate two lists. (Concatenation is equivalent to appending two lists).

Example for Concatenate lists

l1 = [1, 2, 3, 4]
l2 = [5, 6, 7]
print(l1 + l2) 

Output

[1, 2, 3, 4, 5, 6, 7]

Explanation for Concatenate lists
The elements in list1 and list2 are printed by using ‘+’ operator.

10. Iterating through a List

Iterating through the elements of a list as well, is a very useful operation that is frequently used during data analysis.

Example for Iterating through a list

list = [1, 2, 3, 4]
for element in list:
    print(element)

Output

1
2
3
4

Explanation for Iterating through a list
Elements in the list printed in sequence by using iteration.

Conclusion
In this article, we learned about lists. The List supports numerous operations such as adding, multiplying, slicing, membership, and comparison. Lists are used in Python to store the sequence of different data types. Python lists Operations are mutable, which means they can have their elements changed after they’ve been created.

Frequently Asked Questions(FAQ):

1. Which operators can be used with a list?
The + operator joins two lists together. A new list object will be returned by the operator. List append does not append one list to another, but rather appends a single object (in this case, a list) to the end of your current list.A list, like an array, can be used.

2. Python lists can have multiple types?
Any Python type can be included in a list. Although it is uncommon, a list can contain a mix of Python types such as strings, floats, booleans, and so on.

3. Is it possible to change a Python list?
The list is a mutable data type. Elements can be changed after a list has been created. Individual values are replaceable.

4. In Python, how much memory is reserved for a list?
When you create a list object, the list object itself consumes 64 bytes of memory, and each item adds 8 bytes to the list’s size due to references to other objects.