TDIGEST.BYREVRANK

Syntax
TDIGEST.BYREVRANK key reverse_rank [reverse_rank ...]
Available in:
Redis Stack / Bloom 2.4.0
Time complexity:
O(1)

Returns, for each input reverse rank, an estimation of the value (floating-point) with that reverse rank.

Multiple estimations can be retrieved in a signle call.

Required arguments

key is key name for an existing t-digest sketch.
revrank

Reverse rank, for which the value should be retrieved.

0 is the reverse rank of the value of the largest observation.

n-1 is the reverse rank of the value of the smallest observation; n denotes the number of observations added to the sketch.

Return value

Array reply - an array of floating-points populated with value_1, value_2, ..., value_R:

  • Return an accurate result when revrank is 0 (the value of the largest observation)
  • Return an accurate result when revrank is n-1 (the value of the smallest observation), where n denotes the number of observations added to the sketch.
  • Return '-inf' when revrank is equal to n or larger than n

All values are 'nan' if the sketch is empty.

Examples

redis> TDIGEST.CREATE t COMPRESSION 1000
OK
redis> TDIGEST.ADD t 1 2 2 3 3 3 4 4 4 4 5 5 5 5 5
OK
redis> TDIGEST.BYREVRANK t 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
 1) "5"
 2) "5"
 3) "5"
 4) "5"
 5) "5"
 6) "4"
 7) "4"
 8) "4"
 9) "4"
10) "3"
11) "3"
12) "3"
13) "2"
14) "2"
15) "1"
16) "-inf"

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