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ZREMRANGEBYSCORE

Introduction and Use Case(s)​

The ZREMRANGEBYSCORE command is used in Redis to remove all members in a sorted set that have a score within a specified range. Typical use cases include cleaning up expired data, implementing leaderboards where only scores within a certain range are relevant, or managing time-based series data.

Syntax​

ZREMRANGEBYSCORE key min max

Parameter Explanations​

  • key: The name of the sorted set.
  • min: The minimum score (inclusive) of the range. This can be a number or one of the special values -inf (negative infinity) to represent the lowest possible score.
  • max: The maximum score (inclusive) of the range. This can be a number or one of the special values +inf (positive infinity) to represent the highest possible score.

Special modifiers for min and max:

  • Use ( before a number to make the range exclusive. For example, (1 means greater than 1 but not equal to 1.

Return Values​

The command returns the number of elements removed from the sorted set.

Example Output​

(integer) 3

Code Examples​

Remove members with scores between 1 and 2 (inclusive):

dragonfly> ZADD myzset 1 "one" 2 "two" 3 "three"
(integer) 3
dragonfly> ZREMRANGEBYSCORE myzset 1 2
(integer) 2
dragonfly> ZRANGE myzset 0 -1 WITHSCORES
1) "three"
2) "3"

Remove members with scores greater than 1 but less than 3:

dragonfly> ZADD myzset 1 "one" 2 "two" 3 "three"
(integer) 3
dragonfly> ZREMRANGEBYSCORE myzset (1 (3
(integer) 1
dragonfly> ZRANGE myzset 0 -1 WITHSCORES
1) "one"
2) "1"
3) "three"
4) "3"

Best Practices​

  • When working with large data sets, ensure your min and max ranges are correctly defined to avoid unintentional removal of important data.
  • Consider using ZRANGEBYSCORE to preview the elements that will be deleted before executing ZREMRANGEBYSCORE.

Common Mistakes​

  • Confusing inclusive and exclusive boundaries. Always double-check whether you intend to include or exclude the boundary values using parentheses.
  • Not specifying the correct range, which might lead to either no deletions or deletion of more elements than intended.

FAQs​

Q: Can I use floating-point numbers for the score range?

A: Yes, ZREMRANGEBYSCORE supports floating-point numbers for both min and max.

Q: What happens if the specified range does not match any elements?

A: If no elements fall within the specified range, the return value will be (integer) 0, indicating no elements were removed.