"global" calculations for sorted sets

Question

With a sorted set, is there an easy way to compute "global" values, for instance the average, median, max, min, etc. of all the scores in the set, or do I always need to extract the scores and do the calculations myself (which is a bit of a pain ...)?

Answer 1

You can do it all with ZCARD and ZRANGE (withscore of course).

• Min: ZRANGE on index 0
• Max: ZRANGE on max index (ZCARD value)
• Median: ZRANGE on the middle index (ZCARD/2)
• Average: you can store the total off all score in another counter and then divide it by the ZCARD value