Array Deletion at End in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to remove the last element from the list.

DSA Python

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

Drag options to blanks, or click blank then click option'

Aclear

Bpop

Cdelete

Dremove

Attempts:

3 left

💡 Hint

Common Mistakes

Using remove() which needs a value, not an index.

Using clear() which empties the whole list.

The pop() method removes the last item from the list.

2fill in blank

medium

Complete the code to delete the last element using the del statement.

DSA Python

arr = [10, 20, 30, 40]
del arr[1]
print(arr)

Drag options to blanks, or click blank then click option'

A[1]

B[0]

C[-1]

D[:1]

Attempts:

3 left

💡 Hint

Common Mistakes

Using positive indices which delete the first or wrong element.

Using slice notation which deletes multiple elements.

Using del arr[-1] deletes the last element by index.

3fill in blank

hard

Fix the error in the code to remove the last element safely.

DSA Python

arr = []
if arr:
    arr.[1]()
print(arr)

Drag options to blanks, or click blank then click option'

Apop

Bremove

Cclear

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using remove() which needs a value and causes error if list is empty.

Using clear() which empties the whole list.

Using pop() inside a check ensures no error if the list is empty.

4fill in blank

hard

Fill both blanks to remove the last element and print it.

DSA Python

arr = [5, 6, 7]
last = arr[1]()
print([2])

Drag options to blanks, or click blank then click option'

Apop

Blast

Carr

Dremove

Attempts:

3 left

💡 Hint

Common Mistakes

Printing the list instead of the removed element.

Using remove() which needs a value.

pop() removes and returns the last element, which is stored in last.

5fill in blank

hard

Fill all three blanks to remove the last element by index and print the updated list.

DSA Python

arr = [9, 8, 7, 6]
index = [1]
removed = arr.[2](index)
print([3])

Drag options to blanks, or click blank then click option'

A-1

Bpop

Carr

Dremove

Attempts:

3 left

💡 Hint

Common Mistakes

Using remove() which needs a value, not an index.

Printing the removed element instead of the updated list.

Using pop(-1) removes the last element by index and returns it. Printing arr shows the updated list.

Practice

1. What happens when you delete the last element from an array in Python using pop()?

easy

A. The first element is removed and the array size stays the same.

B. The last element is removed and the array size decreases by one.

C. The array is cleared completely.

D. The array becomes empty but elements remain.

Solution

1. Step 1: Understand the pop() method

   The pop() method removes the last element from the array (list) by default.

2. Step 2: Effect on array size

   After removal, the array size decreases by one because one element is deleted.

3. Final Answer:

   The last element is removed and the array size decreases by one. -> Option B

4. Quick Check:

   pop() removes last element [OK]

Hint: pop() removes last item and shrinks array [OK]

Common Mistakes:

• Thinking pop() removes the first element
• Assuming pop() clears the whole array
• Believing array size stays the same after pop()

2. Which of the following is the correct syntax to delete the last element from a list named arr in Python?

easy

A. arr.pop()

B. arr.delete()

C. pop(arr)

D. arr.remove_last()

Solution

1. Step 1: Identify the correct method for deletion at end

   In Python, pop() is the method used to remove the last element from a list.

2. Step 2: Check syntax correctness

   The correct syntax is arr.pop(). Other options are invalid or do not exist in Python.

3. Final Answer:

   arr.pop() -> Option A

4. Quick Check:

   pop() is correct syntax [OK]

Hint: Use arr.pop() to remove last element [OK]

Common Mistakes:

• Using arr.delete() which is invalid
• Trying pop(arr) instead of arr.pop()
• Using arr.remove_last() which does not exist

3. What is the output of the following code?

arr = [10, 20, 30, 40]
arr.pop()
print(arr)

medium

A. [10, 20, 30]

B. [20, 30, 40]

C. [10, 20, 30, 40]

D. [10, 20, 40]

Solution

1. Step 1: Understand pop() effect on arr

   The pop() removes the last element, which is 40.

2. Step 2: Print the updated array

   After removal, the array becomes [10, 20, 30].

3. Final Answer:

   [10, 20, 30] -> Option A

4. Quick Check:

   Last element removed, array shrinks [OK]

Hint: pop() removes last element, print updated list [OK]

Common Mistakes:

• Expecting original array unchanged
• Removing first element instead of last
• Confusing pop() with remove()

4. Find the error in the following code that tries to delete the last element from arr:

arr = [1, 2, 3]
arr.pop(0)
print(arr)

medium

A. pop() deletes the entire array

B. pop() cannot take any arguments

C. pop() should be replaced with remove()

D. pop(0) removes the first element, not the last

Solution

1. Step 1: Analyze pop(0) usage

   pop(0) removes the element at index 0, which is the first element, not the last.

2. Step 2: Identify correct method to delete last element

   To delete the last element, pop() should be called without arguments.

3. Final Answer:

   pop(0) removes the first element, not the last -> Option D

4. Quick Check:

   pop(index) removes element at index [OK]

Hint: pop() without argument removes last element [OK]

Common Mistakes:

• Assuming pop() cannot take arguments
• Using pop(0) to remove last element
• Confusing pop() with remove()

5. Given the list arr = [5, 10, 15, 20, 25], you want to remove the last two elements using pop(). Which code snippet correctly achieves this?

hard

A. arr.pop(1)
arr.pop(0)

B. arr.pop(3)
arr.pop(2)

C. arr.pop()
arr.pop()

D. arr.pop(0)
arr.pop(1)

Solution

1. Step 1: Understand pop() without argument

   Calling pop() without arguments removes the last element each time.

2. Step 2: Apply pop() twice to remove last two elements

   Calling arr.pop() twice removes 25 then 20, the last two elements.

3. Step 3: Check other options

   Options A, B, and C use indices that become invalid or remove wrong elements after first pop.

4. Final Answer:

   arr.pop() followed by arr.pop() -> Option C

5. Quick Check:

   pop() twice removes last two elements [OK]

Hint: Use pop() twice to remove last two elements [OK]

Common Mistakes:

• Using pop() with fixed indices without updating
• Removing first elements instead of last
• Assuming pop() clears multiple elements at once