Array Deletion at End in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

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

DSA Typescript

const arr = [1, 2, 3, 4];
arr.[1]();
console.log(arr);

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

Ashift

Bpush

Cpop

Dunshift

Attempts:

3 left

💡 Hint

Common Mistakes

Using push() instead of pop() which adds elements instead of removing.

Using shift() which removes the first element, not the last.

The pop() method removes the last element from an array.

2fill in blank

medium

Complete the code to remove the last element and store it in a variable.

DSA Typescript

const numbers = [10, 20, 30, 40];
const last = numbers.[1]();
console.log(last);

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

Apop

Bunshift

Cpush

Dshift

Attempts:

3 left

💡 Hint

Common Mistakes

Using push() which adds elements and returns new length, not the element.

Using shift() which removes the first element.

pop() removes the last element and returns it, so it can be stored.

3fill in blank

hard

Fix the error in the code to correctly remove the last element from the array.

DSA Typescript

let fruits = ['apple', 'banana', 'cherry'];
fruits.[1];
console.log(fruits);

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

Apush()

Bpop()

Cpop

Dshift()

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting parentheses, so the method is not executed.

Using push() which adds elements instead of removing.

The method pop() must be called with parentheses to execute and remove the last element.

4fill in blank

hard

Fill both blanks to remove the last element and print the updated array.

DSA Typescript

const colors = ['red', 'green', 'blue'];
colors.[1]();
console.log([2]);

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

Apop

Bcolors

Ccolor

Dpush

Attempts:

3 left

💡 Hint

Common Mistakes

Using push() instead of pop() to remove elements.

Printing a wrong variable name.

Use pop() to remove the last element, then print the updated array colors.

5fill in blank

hard

Fill both blanks to remove the last element, store it, and print both the removed element and updated array.

DSA Typescript

const pets = ['dog', 'cat', 'rabbit'];
const removed = pets.[1]();
console.log(removed);
console.log([2]);

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

Apush

Bpets

Cpop

Dpet

Attempts:

3 left

💡 Hint

Common Mistakes

Using push() which adds elements instead of removing.

Printing a wrong variable name.

pop() removes and returns the last element, which is stored in removed. Then print removed and the updated array pets.

Practice

1. What does the pop() method do when called on an array in TypeScript?

easy

A. Removes the last element from the array and returns it

B. Removes the first element from the array and returns it

C. Adds a new element to the end of the array

D. Returns the length of the array without changing it

Solution

1. Step 1: Understand the pop() method

   The pop() method removes the last element from an array and returns that element.

2. Step 2: Compare with other options

   Other options describe different methods: removing first element is shift(), adding element is push(), and returning length is length property.

3. Final Answer:

   Removes the last element from the array and returns it -> Option A

4. Quick Check:

   pop() removes last element = A [OK]

Hint: pop() always removes from the end of the array [OK]

Common Mistakes:

• Confusing pop() with shift()
• Thinking pop() adds elements
• Assuming pop() returns array length

2. Which of the following is the correct syntax to remove the last element from an array named numbers in TypeScript?

easy

A. numbers.removeLast();

B. numbers.deleteEnd();

C. pop(numbers);

D. numbers.pop();

Solution

1. Step 1: Recall the correct method to remove last element

   The correct method is pop() called on the array object.

2. Step 2: Check syntax correctness

   Only numbers.pop(); is valid TypeScript syntax. Other options are not valid methods or functions.

3. Final Answer:

   numbers.pop(); -> Option D

4. Quick Check:

   Correct pop() syntax = B [OK]

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

Common Mistakes:

• Using non-existent methods like removeLast()
• Calling pop() as a standalone function
• Using incorrect method names

3. What will be the output of the following TypeScript code?

let fruits = ['apple', 'banana', 'cherry'];
let removed = fruits.pop();
console.log(fruits);
console.log(removed);

medium

A. ['apple', 'banana', 'cherry'] and 'cherry'

B. ['apple', 'banana', 'cherry'] and undefined

C. ['apple', 'banana'] and 'cherry'

D. ['apple', 'banana'] and 'banana'

Solution

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

   Calling pop() removes the last element 'cherry' from fruits and returns it.

2. Step 2: Trace the console.log outputs

   After pop, fruits is ['apple', 'banana'] and removed is 'cherry'.

3. Final Answer:

   ['apple', 'banana'] and 'cherry' -> Option C

4. Quick Check:

   pop() removes last element = D [OK]

Hint: pop() returns removed last element and shortens array [OK]

Common Mistakes:

• Expecting pop() to remove first element
• Thinking pop() returns the new array
• Confusing removed element with array length

4. Identify the error in the following TypeScript code that tries to remove the last element from an array items:

let items = [10, 20, 30];
items.pop;
console.log(items);

medium

A. Missing parentheses after pop method call

B. pop method does not exist on arrays

C. pop should be called as a standalone function

D. pop removes the first element, not last

Solution

1. Step 1: Check method call syntax

   The code uses items.pop; without parentheses, so the method is not called.

2. Step 2: Understand consequences

   Without parentheses, pop is just a reference, so the array remains unchanged.

3. Final Answer:

   Missing parentheses after pop method call -> Option A

4. Quick Check:

   pop() needs () to execute = A [OK]

Hint: Always use () to call methods like pop() [OK]

Common Mistakes:

• Forgetting parentheses on method calls
• Thinking pop is a standalone function
• Confusing pop with shift

5. Given the array let nums = [5, 10, 15, 20];, which code snippet correctly removes the last two elements and returns the modified array?

hard

A. nums.pop(2); return nums;

B. nums.pop(); nums.pop(); return nums;

C. nums.splice(-2, 1); return nums;

D. nums.removeLast(2); return nums;

Solution

1. Step 1: Understand pop() removes one element at a time

   Calling pop() twice removes last two elements one by one.

2. Step 2: Check other options

   splice(-2, 1) removes only one element. pop(2) and removeLast(2) are invalid methods.

3. Final Answer:

   nums.pop(); nums.pop(); return nums; -> Option B

4. Quick Check:

   pop() removes one element; call twice for two [OK]

Hint: Call pop() twice to remove two elements from end [OK]

Common Mistakes:

• Trying pop() with arguments
• Using splice with incorrect parameters
• Using non-existent methods like removeLast