ZSCORE

The ZSCORE command returns the score of a specified member in a sorted set. If the member does not exist, nil is returned.

The time complexity of the ZSCORE command is O(1).

Redis Native Command Syntax

ZSCORE key member

Parameter Description

• key: The key of the sorted set
• member: The name of the member

Detailed Explanation

The ZSCORE command is used to get the score of a specified member in a sorted set. If the member does not exist in the sorted set, nil is returned. If the key does not exist, nil is also returned.

Return Value

• If the member exists, return its score (in string form)
• If the member does not exist or the key does not exist, return nil

Example

redis> ZADD myzset 1 "one"
(integer) 1
redis> ZSCORE myzset "one"
"1"
redis> ZSCORE myzset "two"
(nil)

Redisun Usage

In redisun, the ZSCORE command is implemented through the ZScoreCommand class and the zscore method in the Redisun class.

Basic Usage

Redisun redisun = Redisun.create(options -> {
  options.setHost("localhost");
  options.setPort(6379);
});

// Add some test data
redisun.zadd("myzset", 1.0, "one");
redisun.zadd("myzset", 2.5, "two");

// Get the score of a member
Double score = redisun.zscore("myzset", "one");
System.out.println("Score of 'one': " + score); // Output: Score of 'one': 1.0

// Get the score of a non-existent member
Double nonExistentScore = redisun.zscore("myzset", "three");
System.out.println("Score of 'three': " + nonExistentScore); // Output: Score of 'three': null

Asynchronous Usage

// Asynchronously get the score of a member
CompletableFuture<Double> future = redisun.asyncZscore("myzset", "one");

// Handle asynchronous result
future.thenAccept(score -> {
  if (score != null) {
      System.out.println("Score: " + score);
  } else {
      System.out.println("Member not found");
  }
});

Notes

1. If the member does not exist, the method returns null
2. If the key does not exist, the method also returns null
3. The score is returned as a Double type

References

• Redis ZSCORE Command Official Documentation