Python: Change or Modify List

There are several ways to change or modify list items:

1. By using insert()

It is a in-built function inserts a given element at a given index in a list. Each item within a list has an index number associated with that item (starting from zero).We can modify an item within a list in Python by referring to the item’s index.

Syntax:

list_name.insert(index, element)

Example:

thislist = ["apple", "banana", "cherry"]
print("List before insert: ",thislist)

thislist[1] = "papaya"
print("List after insert: ",thislist)

Output:

List before insert:  ['apple', 'banana', 'cherry']
List after insert:  ['apple', 'papaya', 'cherry']

2. By using append()

We can update single or multiple elements of lists by giving the slice on the left-hand side of the assignment operator, and you can add to elements in a list with the append() method.

mylist = ['physics','chemistry']
print("List before append: ",mylist)

mylist.append('biology')
print("List after append: ",mylist)

Output:

List before append:  ['physics', 'chemistry']
List after append:  ['physics', 'chemistry', 'biology']

3. By using Index no

To change the value of a specific item, refer to the index number.

mylist = [1,2,3,4,5]
print("list before: ",mylist)

mylist[2] = 6
print("list after: ",mylist)

Output:

list before:  [1, 2, 3, 4, 5]
list after:  [1, 2, 6, 4, 5]

4. By using extend()

It is used to  adds all the elements of an iterable (list, tuple, string etc.) to the end of the list.

languages = ['French', 'English']
print("List before extend: ",languages);

languages.extend(['Hindi'])
print("List after extend: ",languages);

Output:

List before extend:  ['French', 'English']
List after extend:  ['French', 'English', 'Hindi']

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