LPOP and RPOP for removal in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to remove and return the first element from the list stored at key.

Redis

redis.call('[1]', 'mylist')

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

ARPOP

BPOP

CLPOP

DREMOVE

Attempts:

3 left

💡 Hint

Common Mistakes

Using RPOP instead of LPOP removes from the right side.

Using POP or REMOVE commands which do not exist in Redis.

The LPOP command removes and returns the first element of the list.

2fill in blank

medium

Complete the code to remove and return the last element from the list stored at key.

Redis

redis.call('[1]', 'mylist')

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

ARPOP

BLPOP

CPOP

DDEL

Attempts:

3 left

💡 Hint

Common Mistakes

Using LPOP instead of RPOP removes from the left side.

Using POP or DEL commands which do not remove list elements.

The RPOP command removes and returns the last element of the list.

3fill in blank

hard

Fix the error in the code to correctly remove the first element from the list 'tasks'.

Redis

redis.call('[1]', 'tasks')

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

ADEL

BPOP

CREMOVE

DLPOP

Attempts:

3 left

💡 Hint

Common Mistakes

Using POP or REMOVE which are invalid commands.

Using DEL which deletes the whole key, not an element.

Only LPOP correctly removes the first element from a Redis list.

4fill in blank

hard

Fill both blanks to remove the last element from 'queue' and the first element from 'stack'.

Redis

redis.call('[1]', 'queue')
redis.call('[2]', 'stack')

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

ARPOP

BLPOP

CDEL

DPOP

Attempts:

3 left

💡 Hint

Common Mistakes

Using DEL deletes the entire key, not an element.

Using POP which is not a Redis list command.

RPOP removes the last element, and LPOP removes the first element from Redis lists.

5fill in blank

hard

Fill all three blanks to remove the first element from 'list1', the last element from 'list2', and the first element from 'list3'.

Redis

redis.call('[1]', 'list1')
redis.call('[2]', 'list2')
redis.call('[3]', 'list3')

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

ARPOP

BLPOP

DDEL

Attempts:

3 left

💡 Hint

Common Mistakes

Using DEL instead of LPOP or RPOP.

Mixing up LPOP and RPOP commands.

Use LPOP to remove the first element and RPOP to remove the last element from Redis lists.