SCARD for set size in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the number of elements in the set named 'myset'.

Redis

SCARD [1]

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

Acountset

Bsetcount

Celements

Dmyset

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong set name that does not exist.

Forgetting to provide the set name after SCARD.

The SCARD command returns the number of elements in the specified set. Here, the set is named myset.

2fill in blank

medium

Complete the code to find the size of the set stored in the variable 'setKey'.

Redis

SCARD [1]

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

AsetKey

Bsetkey

CSetKey

Dset_key

Attempts:

3 left

💡 Hint

Common Mistakes

Changing the case of the key name.

Using underscores or other characters not in the key.

Redis commands are case-sensitive for keys. Use the exact variable name setKey as the set name.

3fill in blank

hard

Fix the error in the command to get the set size of 'users'.

Redis

SCARD [1]

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

Ausers

Buser

CuserSet

Duser_set

Attempts:

3 left

💡 Hint

Common Mistakes

Using a singular form instead of plural.

Adding extra characters or underscores.

The set name is users. Using user or other variants will cause Redis to look for a different key.

4fill in blank

hard

Fill both blanks to get the size of the set named 'activeUsers' and store it in variable 'count'.

Redis

count = [1]([2]) activeUsers

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

Aredis.call

BSCARD

Cget

DSET

Attempts:

3 left

💡 Hint

Common Mistakes

Using get which is for strings, not sets.

Using SET which is for setting values, not getting size.

In Redis scripting, redis.call is used to run commands like SCARD to get the size of a set.

5fill in blank

hard

Fill all three blanks to write a Lua script that returns the size of the set given by the first key argument.

Redis

return [1]([2], [3][1])

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

Aredis.call

BKEYS

CSCARD

DARGV

Attempts:

3 left

💡 Hint

Common Mistakes

Using ARGV instead of KEYS for keys.

Using get instead of SCARD.

This Lua script calls redis.call with the command SCARD on the first key in KEYS to get the set size.