TDIGEST.BYRANK

Returns, for each input rank, a floating-point estimation of the value with that rank. Multiple estimations can be retrieved in a single call.

Required arguments

<details open><summary><code>key</code></summary>

is the key name of an existing t-digest sketch.

</details> <details open><summary><code>rank</code></summary>

Ranks for which the values should be retrieved.

0 is the rank of the value of the smallest observation.

n-1 is the rank of the value of the largest observation, where n denotes the number of observations that have been added to the sketch.

</details>

Example

{{< highlight bash >}} 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.BYRANK t 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

1. "1"
2. "2"
3. "2"
4. "3"
5. "3"
6. "3"
7. "4"
8. "4"
9. "4"
10. "4"
11. "5"
12. "5"
13. "5"
14. "5"
15. "5"
16. "inf" {{< / highlight >}}

Redis Software and Redis Cloud compatibility

| Redis Software | Redis Cloud | <span style="min-width: 9em; display: table-cell">Notes</span> | |:----------------------|:-----------------|:------| | <span title="Supported">✅ Supported</span> | <span title="Supported"><nobr>✅ Flexible & Annual</nobr></span> <span title="Supported">✅ Free & Fixed</nobr></span> | |

Return information

{{< multitabs id="tdigest-byrank-return-info" tab1="RESP2" tab2="RESP3" >}}

One of the following:

• [Array]({{< relref "/develop/reference/protocol-spec#arrays" >}}) of [bulk strings]({{< relref "/develop/reference/protocol-spec#bulk-strings" >}}) as floating-points, populated with value_1, value_2, ..., value_R:
  • an accurate result when rank is 0, the value of the smallest observation.
  • an accurate result when rank is n-1, the value of the largest observation, where n denotes the number of observations added to the sketch.
  • inf when rank is equal to n or larger than n.
  • nan for all ranks when the given sketch is empty.
• [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}) in these cases: the given key does not exist or is of an incorrect type, rank parsing errors, or incorrect number of arguments.

-tab-sep-

One of the following:

• [Array]({{< relref "/develop/reference/protocol-spec#arrays" >}}) of [doubles]({{< relref "/develop/reference/protocol-spec#doubles" >}}) as floating-points, populated with value_1, value_2, ..., value_R:
  • an accurate result when rank is 0, the value of the smallest observation.
  • an accurate result when rank is n-1, the value of the largest observation, where n denotes the number of observations added to the sketch.
  • inf when rank is equal to n or larger than n.
  • nan for all ranks when the given sketch is empty.
• [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}) in these cases: the given key does not exist or is of an incorrect type, rank parsing errors, or incorrect number of arguments.

{{< /multitabs >}}