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ZRANGEBYLEX

Returns a range of members in a sorted set, by lexicographical order, within the given lexicographical range.

Syntax​

ZRANGEBYLEX key min max [LIMIT offset count]

Parameters​

  • key: The name of the sorted set.
  • min: The minimum lexicographical value (inclusive) of the range. The range can be inclusive ([value) or exclusive ((value).
  • max: The maximum lexicographical value (inclusive) of the range. The range can be inclusive ([value) or exclusive ((value).
  • LIMIT offset count: Optional. Specifies the number of members to return starting from the offset. If not provided, the entire range is returned.

Details​

  • Available since: 2.8.9
  • Time complexity: O(log(N) + M) where N is the number of elements in the sorted set, and M is the number of elements being returned.
  • ACL categories: @read, @sortedset, @slow

The ZRANGEBYLEX command is used to retrieve members in a sorted set stored at key within the specified lexicographical range, ordered by lexicographical order. This command is useful when the elements in the sorted set are strings and you want to perform a range query on those strings.

Special Range Syntax​

  • Inclusive Range: Use [ followed by the value (e.g., [a).
  • Exclusive Range: Use ( followed by the value (e.g., (a).
  • Unbounded Range: Use - for the minimum and + for the maximum to specify an open-ended range.

Examples​

Basic Usage​

Assume we have a sorted set called myzset with the following members:

ZADD myzset 0 "apple" 0 "banana" 0 "cherry" 0 "date" 0 "fig"

To retrieve members between "banana" and "date" (inclusive):

ZRANGEBYLEX myzset [banana [date

This will return:

1) "banana"
2) "cherry"
3) "date"

Using Exclusive Range​

To retrieve members between "banana" (exclusive) and "date" (exclusive):

ZRANGEBYLEX myzset (banana (date

This will return:

1) "cherry"

Using Unbounded Range​

To retrieve all members up to "date":

ZRANGEBYLEX myzset - [date

This will return:

1) "apple"
2) "banana"
3) "cherry"
4) "date"

Using LIMIT​

To retrieve the first two members starting from "banana":

ZRANGEBYLEX myzset [banana [date LIMIT 0 2

This will return:

1) "banana"
2) "cherry"

Edge Cases​

  • If min is greater than max, ZRANGEBYLEX returns an empty array.
  • If the key does not exist, ZRANGEBYLEX returns an empty array.
  • If the key exists but is not a sorted set, an error is returned.

RESP2/RESP3 Reply​

  • Array reply: list of members in the specified lexicographical range.