Python Coding challenge - Day 183 | What is the output of the following Python Code?

 

Code:

x = [1, 2, 3]

y = x[:-1]

x[-1] = 4

print(y)

Solution and Explanation: 

Let's break down what happens step by step:

x = [1, 2, 3]: Here, a list x is created with elements [1, 2, 3].

y = x[:-1]: This line creates a new list y by slicing x from the beginning to the second-to-last element. So, y will contain [1, 2].

x[-1] = 4: This line modifies the last element of list x to be 4. After this operation, x becomes [1, 2, 4].

print(y): Finally, y is printed. Since y was created as a result of slicing x before the modification, it remains unchanged. Therefore, it prints [1, 2].

Here's the breakdown:

Initially, x = [1, 2, 3].

y = x[:-1] makes y equal to a slice of x from the beginning to the second-to-last element, [1, 2].

x[-1] = 4 changes the last element of x to 4, so x becomes [1, 2, 4].

Since y was created independently of x, modifying x does not affect y, so print(y) outputs [1, 2].