List in python is mutable types which means it can be changed after assigning some value. The list is similar to arrays in other programming languages. In this article, we are going to see how to change list items in python.
Let’s understand first how to access elements in python:
- Accessing the first element mylist[0]
- Accessing the second element mylist[1]
- Accessing the last element mylist[-1] or mylist[len(mylist)-1]
Python3
# codegfg = [ 10, 20, 30, 40, 50, 60] #first elementprint(gfg[0]) #second elementprint(gfg[1]) #last elementprint(gfg[-1]) |
Output:
10 20 60
Now we can change the item list with a different method:
Example 1: Change Single list item.
Approach:
- Change first element mylist[0]=value
- Change third element mylist[2]=value
- Change fourth element mylist[3]=value
Code:
Python3
# listList=[ 10, 20, 30, 40, 50, 60]print("original list ")print(List) #changing the first valueList[0] = 11 #changing the second valueList[1] = 21 #changing the last elementList[ -1] = 61 print("\nNew list")print(List) |
Output:
original list [10, 20, 30, 40, 50, 60] New list [11, 21, 30, 40, 50, 61]
Example 2: Changing all values using loops.
Python3
# listlist = [ 10, 20, 30, 40, 50, 60]print("Original list ")print(list) print("After incrementing each element of list by 2") # adding 2 to each value of list# len method to calculate length of list# range method is used to go upto a certain rangefor i in range( len(list)): list[i] = list[i] + 2 print(list) |
Output:
Original list [10, 20, 30, 40, 50, 60] After incrementing each element of list by 2 [12, 22, 32, 42, 52, 62]
Example 3: Changing all values of a list using List comprehension.
Python3
# listList_1 = [ 10, 20, 30, 40, 50]print("Original list ")print(List_1) print("After incrementing each element of list by 2")List_2=[ i+2 for i in List_1] print(List_2) |
Output:
Original list [10, 20, 30, 40, 50] After incrementing each element of list by 2 [12, 22, 32, 42, 52]
