How To Replace A Number In List Python

In this tutorial, we are going to learn how to replace a number in a list using Python. This is particularly helpful when you need to change the value of a specific element in a list based on a certain condition.

Step 1: Create a List

First of all, let’s create a list with some elements. Here’s a sample list:

1	numbers = [10, 20, 30, 40, 50]

In our example, we have a list of integers. However, you can have a list with any data type you want.

Step 2: Identify the Index of the Element to be Replaced

Now let’s decide which element we want to replace. For that, we need to know the index of that element. In Python, list indexes start from 0. So, in our example, the index of the first element (10) is 0, the index of the second element (20) is 1, and so on.

For this tutorial, let’s replace the third element (30). So, the index we need is 2.

Step 3: Assign a New Value to the Element

To replace a number in a list, you simply need to assign a new value to it using the assignment operator =. Here’s how you can do that:

1	numbers[2] = 25

After this code runs, the new list will be:

[10, 20, 25, 40, 50]

As you can see, the third element (30) is replaced with the new value (25).

Step 4: Replace an Element using a Condition

In some cases, you might want to replace an element based on a certain condition. For example, you might want to replace all occurrences of a specific value. You can do that using a loop and an if statement. Here’s an example:

numbers = [10, 20, 30, 30, 40, 50]

for index, value in enumerate(numbers):

if value == 30:

numbers[index] = 35

print(numbers)

This code will replace all occurrences of 30 with the new value 35:

[10, 20, 35, 35, 40, 50]

Full Code

Here’s the full code that demonstrates how to replace a number in a list:

numbers = [10, 20, 30, 30, 40, 50]

# Replace the third element

numbers[2] = 25

# Replace all occurrences of 30 with 35