The ZRANK command returns the ranking of members in an ordered set, arranged based on ascending fractions. For example, if the member "alice" scores the lowest, ZRANK user_scores alice returns 0; if it is the third lowest, it returns 2. When the scores are the same, Redis is sorted dictionary. If the key or member does not exist, nil is returned. To get the descending ranking, use the ZREVRANK command. Common considerations include: index starts from 0, processing score parallelism, confirming that the key type is an ordered set, and testing whether ZRANK returns nil if it exists. Applicable scenarios include game rankings, user rankings, progress bar display, etc., with a time complexity of O(log N), which is highly efficient. In short, when using ZRANK, you need to pay attention to its zero-based index and parallel sorting mechanism, and use ZREVRANK when descending order is required.

To get the rank of a member in a sorted set using Redis, you use the ZRANK command. It returns the zero-based index of the member based on its score in ascending order. If the key or member doesn't exist, it returns nil . That's the basic idea — now let's break down how and when to use it.

What does ZRANK actually return?

When you run ZRANK key member , Redis looks at the sorted set stored under the given key and finds where that member sits in the list ordered by score from low to high. The result is the index position — starting at 0 for the first item.

For example:

 ZRANK user_scores alice

If alice has the lowest score, this would return 0 . If she's third from the bottom, you get 2 .

• If there are ties in scores, Redis sorts members lexicographically.
• Only works with existing keys and members — otherwise, you'll get nil .

So if you're expecting a number and see nil , double-check whether the key and member both exist.

How to handle descending rank?

Redis doesn't directly support getting the rank in descending order with ZRANK . But there's a way around it: use ZREVRANK .

It works just like ZRANK , but give you the rank as if the elements were sorted from highest to lowest.

Example:

 ZREVRANK user_scores alice

This tells you Alice's position in a leaderboard sorted from top to bottom.

So if your app shows rankings in both directions (like a game with "top players" and "bottom players"), you'll want to use both commands depending on context.

Common mistakes and things to watch out for

Here are a few gotchas people often miss:

• Index starts at 0 – Don't forget it's zero-based. So if you're displaying rankings to users, you might need to add 1 before showing the result.
• Tied scores still have order – When two members have the same score, Redis uses lexicographical ordering to determine who comes first. This can affect results unexpectedly if you don't know it.
• Check data type – Make sure the key is a sorted set. Trying to use ZRANK on a regular set or string will throw an error.
• Use ZEXISTS? No such command – To check if a member exists, just run ZRANK and see if it returns nil .

So always test with known values ??before relying on it in production logic.

When should you use ZRANK?

You'll find ZRANK useful whenever you need to know a member's position in a sorted collection. Common use cases include:

• Game leaderboards
• Ranking users by points, activity, or stats
• Showing progress bars or percentile ranks
• Caching and comparing relative positions without full list retrieval

Just keep in mind that ZRANK is fast — O(log N) time complexity — so even with large sets, it won't bog things down.

That's how you get a member's rank with ZRANK . Not too complicated once you understand how it indexes and handles ties. Just remember to use ZREVRANK when you need descending order and be careful with zero-based results.

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