Pagination with limit and offset in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this pagination API call?

Consider an API endpoint that returns a list of items with pagination using limit and offset query parameters. The data source contains 10 items labeled from 1 to 10.

The API call is: GET /items?limit=3&offset=4

What list of item IDs will the API return?

Rest API

items = list(range(1, 11))
limit = 3
offset = 4
result = items[offset:offset+limit]
print(result)

A [4, 5, 6]

B [5, 6, 7]

C [6, 7, 8]

D [3, 4, 5]

💡 Hint

Remember that list indexing in Python starts at 0, so offset 4 means the 5th item.

The offset 4 means start from the 5th item (index 4). With limit 3, the API returns items at indices 4, 5, and 6, which are 5, 6, and 7.

🧠 Conceptual

intermediate

Which statement about limit and offset pagination is true?

Choose the correct statement about using limit and offset for pagination in REST APIs.

A Offset and limit are interchangeable and mean the same thing.

B Limit specifies the starting item index, and offset specifies the number of items to return.

C Offset specifies how many items to skip, and limit specifies how many items to return.

D Limit specifies the total number of items in the data source.

💡 Hint

Think about how you would get the next page of results.

Offset tells the API how many items to skip before starting to return results. Limit tells how many items to return after skipping.

🔧 Debug

advanced

Why does this pagination code return an empty list?

Given the following code snippet for pagination, why does it return an empty list?

Rest API

items = list(range(1, 21))
limit = 5
offset = 20
result = items[offset:offset+limit]
print(result)

A Because offset is equal to the length of the list, so slicing starts beyond the last item.

B Because limit is too small to return any items.

C Because the list is empty.

D Because offset and limit are swapped in the slice.

💡 Hint

Check the length of the list and the value of offset.

The list has 20 items indexed 0 to 19. Offset 20 means start slicing at index 20, which is beyond the last item, so the slice returns an empty list.

📝 Syntax

advanced

Which option correctly implements pagination with limit and offset in Python?

Choose the code snippet that correctly returns a paginated list of items using limit and offset.

A result = items[offset:offset+limit]

B result = items[limit:offset+limit]

C result = items[offset-limit:offset]

D result = items[limit-offset:limit]

💡 Hint

Remember slicing syntax is list[start:end] where start is inclusive and end is exclusive.

To get items starting at offset and up to limit items, slice from offset to offset+limit.

🚀 Application

expert

How many items will be returned by this paginated API call?

An API has 15 items. A client requests GET /items?limit=7&offset=10. How many items will the API return?

A 0

B 7

C 10

D 5

💡 Hint

Calculate how many items remain after skipping the offset.

Offset 10 skips the first 10 items, leaving 5 items (15 - 10). Limit 7 means up to 7 items can be returned, but only 5 remain, so 5 items are returned.

Practice

1.

What does the limit parameter control in pagination?

easy

A. The starting position of items to return

B. The sorting order of the items

C. The total number of items in the database

D. The number of items to return in one page

Solution

1. Step 1: Understand the role of limit

   The limit parameter sets how many items you want to get back in one page of results.

2. Step 2: Differentiate from offset

   The offset controls where to start, not how many items to return.

3. Final Answer:

   The number of items to return in one page -> Option D

4. Quick Check:

   limit = number of items per page [OK]

Hint: Limit sets count of items per page, offset sets start point [OK]

Common Mistakes:

• Confusing limit with offset
• Thinking limit controls sorting
• Assuming limit is total items

2.

Which of the following is the correct way to request the second page of results with 10 items per page using limit and offset?

GET /items?limit=10&offset=?

easy

A. 10

B. 20

C. 0

D. 1

Solution

1. Step 1: Calculate offset for second page

   For page 1, offset is 0. For page 2, offset = limit * (page_number - 1) = 10 * (2 - 1) = 10.

2. Step 2: Confirm limit remains 10

   Limit stays 10 to get 10 items per page.

3. Final Answer:

   10 -> Option A

4. Quick Check:

   offset = limit * (page - 1) = 10 [OK]

Hint: Offset = limit x (page number - 1) [OK]

Common Mistakes:

• Using offset = page number
• Using offset = limit x page number
• Setting offset to 0 for second page

3.

Given the following API call, what items will be returned if the full list is ["a", "b", "c", "d", "e", "f"]?

GET /items?limit=2&offset=3

medium

A. ["d", "e"]

B. ["c", "d"]

C. ["a", "b"]

D. ["e", "f"]

Solution

1. Step 1: Understand offset and limit

   Offset 3 means start from the 4th item (0-based index), which is "d".

2. Step 2: Select 2 items from offset

   Limit 2 means take 2 items starting at "d", so items are "d" and "e".

3. Final Answer:

   ["d", "e"] -> Option A

4. Quick Check:

   Start at index 3, take 2 items = ["d", "e"] [OK]

Hint: Offset is start index, limit is count from there [OK]

Common Mistakes:

• Starting count at 1 instead of 0
• Taking wrong slice of items
• Confusing offset and limit roles

4.

Identify the error in this API call for pagination: GET /items?limit=5&offset=-10

medium

A. Offset should be a string

B. Limit cannot be 5

C. Negative offset is invalid

D. Limit must be greater than offset

Solution

1. Step 1: Check offset value

   Offset represents the starting position and cannot be negative because you cannot start before the first item.

2. Step 2: Validate limit and offset rules

   Limit can be any positive number; offset must be zero or positive.

3. Final Answer:

   Negative offset is invalid -> Option C

4. Quick Check:

   Offset ≥ 0 required [OK]

Hint: Offset must never be negative [OK]

Common Mistakes:

• Allowing negative offset
• Confusing limit and offset roles
• Assuming offset can be string

5.

You have 53 items and want to paginate with limit=10. How many pages will you have, and what is the offset for the last page?

hard

A. 5 pages, offset 40

B. 6 pages, offset 50

C. 6 pages, offset 45

D. 7 pages, offset 60

Solution

1. Step 1: Calculate total pages

   Total pages = ceiling of total items / limit = ceil(53 / 10) = 6 pages.

2. Step 2: Calculate offset for last page

   Offset for last page = limit x (pages - 1) = 10 x (6 - 1) = 50.

3. Final Answer:

   6 pages, offset 50 -> Option B

4. Quick Check:

   Pages = 6, offset last = 50 [OK]

Hint: Pages = ceil(total/limit), offset = limit x (pages-1) [OK]

Common Mistakes:

• Using floor instead of ceiling for pages
• Calculating offset as limit x pages
• Ignoring leftover items on last page