Array Insertion at End in DSA Python - Practice Problems & Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output after inserting elements at the end of the array?

Consider the following Python code that inserts elements at the end of an array (list). What will be printed?

DSA Python

arr = [1, 2, 3]
arr.append(4)
arr.append(5)
print(arr)

A [5, 4, 3, 2, 1]

B [4, 5, 1, 2, 3]

C [1, 2, 3, 4, 5]

D [1, 2, 3]

💡 Hint

Remember that append adds elements to the end of the list.

The append method adds elements at the end of the list. So after appending 4 and 5, the list becomes [1, 2, 3, 4, 5].

❓ Predict Output

intermediate

What is the final array after multiple insertions at the end?

What will be the output of this code snippet?

DSA Python

arr = []
for i in range(3):
    arr.append(i * 2)
print(arr)

A [0, 1, 2]

B [0, 2, 4]

C [2, 4, 6]

D []

💡 Hint

Check the values generated by i * 2 for i in range(3).

The loop runs for i = 0, 1, 2. Multiplying by 2 gives 0, 2, 4. These are appended in order.

🔧 Debug

advanced

Identify the error in this array insertion code

What error will this code produce when run?

DSA Python

arr = [1, 2, 3]
arr.append(4, 5)
print(arr)

A No error, output: [1, 2, 3, 4, 5]

B SyntaxError: invalid syntax

C ValueError: too many values to unpack

D TypeError: append() takes exactly one argument (2 given)

💡 Hint

Check how many arguments append accepts.

The append method accepts only one argument. Passing two causes a TypeError.

🚀 Application

advanced

What is the array after inserting elements using extend?

Given the code below, what will be the final state of the array?

DSA Python

arr = [1, 2]
arr.extend([3, 4])
print(arr)

A [1, 2, 3, 4]

B [[1, 2], 3, 4]

C [1, 2, [3, 4]]

D [3, 4, 1, 2]

💡 Hint

Remember that extend adds each element of the iterable individually.

The extend method adds each element of the given list to the end of the original list.

🧠 Conceptual

expert

How many elements are in the array after these insertions?

If we start with an empty array and perform these operations, how many elements will the array have at the end? arr = [] arr.append(1) arr.append([2, 3]) arr.extend([4, 5])

A 4

B 5

C 3

D 6

💡 Hint

Remember append adds the whole object as one element, extend adds each element separately.

After append(1), array has 1 element.
append([2, 3]) adds the list as one element, total 2.
extend([4, 5]) adds two elements individually, total 4.