Unique visitor tracking with sets in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a visitor ID to the set of unique visitors for today.

Redis

SADD unique_visitors:2024-06-01 [1]

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

Avisitor123

BGET

CDEL

DSET

Attempts:

3 left

💡 Hint

Common Mistakes

Using commands like GET or DEL instead of the visitor ID.

Forgetting to specify the visitor ID.

The SADD command adds a member to a set. Here, we add the visitor ID visitor123 to the set unique_visitors:2024-06-01.

2fill in blank

medium

Complete the code to count how many unique visitors visited today.

Redis

SCARD [1]

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

Avisitors_today

Bvisitor_count

Cunique_visitors:2024-06-01

Dunique_visitors

Attempts:

3 left

💡 Hint

Common Mistakes

Using a key that does not exist or is not a set.

Confusing SCARD with other commands like GET.

The SCARD command returns the number of members in a set. We use the key unique_visitors:2024-06-01 to count today's unique visitors.

3fill in blank

hard

Fix the error in the code to get the union of unique visitors from two days.

Redis

SUNION unique_visitors:2024-06-01 [1]

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

Aunique_visitors:2024-06-01

Bunique_visitors:2024-06-03

Cunique_visitors

Dunique_visitors:2024-06-02

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same key twice.

Using a key that does not exist.

The SUNION command returns the union of sets. To get visitors from two days, use the keys for those days. Here, we fix the second key to unique_visitors:2024-06-02.

4fill in blank

hard

Fill both blanks to store the union of two days' unique visitors into a new set.

Redis

SUNIONSTORE [1] unique_visitors:2024-06-01 [2]

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

Aunique_visitors:2024-06-01-02

Bunique_visitors:2024-06-03

Cunique_visitors:2024-06-02

Dunique_visitors:2024-06-04

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up source and destination keys.

Using keys that do not exist.

SUNIONSTORE saves the union of sets into a new key. We store the union of unique_visitors:2024-06-01 and unique_visitors:2024-06-02 into unique_visitors:2024-06-01-02.

5fill in blank

hard

Fill all three blanks to find the intersection of three days' unique visitors and store it in a new set.

Redis

SINTERSTORE [1] unique_visitors:2024-06-01 [2] [3]

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

Aunique_visitors:2024-06-01-02-03

Bunique_visitors:2024-06-02

Cunique_visitors:2024-06-03

Dunique_visitors:2024-06-04

Attempts:

3 left

💡 Hint

Common Mistakes

Using keys that do not exist.

Confusing intersection with union commands.

SINTERSTORE stores the intersection of sets into a new key. Here, we find visitors common to June 1, 2, and 3, and store them in unique_visitors:2024-06-01-02-03.