Python Coding Challenge - Question with Answer (ID -190126)

 

Let’s break this down line by line 👇

lst = [1, 2, 3]

Here, you create a list named lst with three elements: 1, 2, and 3.

So right now:

lst = [1, 2, 3]

Length = 3

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lst.append([4, 5])

Now you use append(). Important point:

👉 append() adds the ENTIRE item as a single element

You are NOT adding 4 and 5 separately.
You are adding a list [4, 5] as one single element.

So after append:

lst = [1, 2, 3, [4, 5]]

Now the list contains 4 elements:

1 

2

 3

[4, 5] → (this is one nested list, counted as ONE element)

---

print(len(lst))

len(lst) counts total elements in the outer list.

So the output is:

4

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 Common Confusion (Important!)

If you had used extend() instead of append(), the result would be different:

lst = [1, 2, 3]
lst.extend([4, 5])
print(len(lst))

Now:

lst = [1, 2, 3, 4, 5]

Output would be 5

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