TDIGEST.RANK

Returns, for each floating-point input value, the estimated rank of the value (the number of observations in the sketch that are smaller than the value + half the number of observations that are equal to the value). Multiple ranks can be retrieved in a single call.

Required arguments

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

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

</details> <details open><summary><code>value</code></summary>

is the input value for which the rank should be estimated.

</details>

Examples

{{< highlight bash >}} redis> TDIGEST.CREATE s COMPRESSION 1000 OK redis> TDIGEST.ADD s 10 20 30 40 50 60 OK redis> TDIGEST.RANK s 0 10 20 30 40 50 60 70

1. (integer) -1
2. (integer) 0
3. (integer) 1
4. (integer) 2
5. (integer) 3
6. (integer) 4
7. (integer) 5
8. (integer) 6 redis> TDIGEST.REVRANK s 0 10 20 30 40 50 60 70
9. (integer) 6
10. (integer) 5
11. (integer) 4
12. (integer) 3
13. (integer) 2
14. (integer) 1
15. (integer) 0
16. (integer) -1
    {{< / highlight >}}

{{< highlight bash >}} redis> TDIGEST.CREATE s COMPRESSION 1000 OK redis> TDIGEST.ADD s 10 10 10 10 20 20 OK redis> TDIGEST.RANK s 10 20

1. (integer) 2
2. (integer) 5 redis> TDIGEST.REVRANK s 10 20
3. (integer) 4
4. (integer) 1 {{< / 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-rank-return-info" tab1="RESP2" tab2="RESP3" >}}

One of the following:

• [Array]({{< relref "/develop/reference/protocol-spec#arrays" >}}) of [integers]({{< relref "/develop/reference/protocol-spec#integers" >}}) populated with rank_1, rank_2, ..., rank_V:

  • -1 when value is smaller than the value of the smallest observation.
  • The number of observations when value is larger than the value of the largest observation.
  • Otherwise, an estimation of the number of (observations smaller than value + half the observations equal to value).

  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 added to the sketch.

  All values are -2 if the 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, quantile parsing errors, or incorrect number of arguments.

-tab-sep-

One of the following:

• [Array]({{< relref "/develop/reference/protocol-spec#arrays" >}}) of [integers]({{< relref "/develop/reference/protocol-spec#integers" >}}) populated with rank_1, rank_2, ..., rank_V:

  • -1 when value is smaller than the value of the smallest observation.
  • The number of observations when value is larger than the value of the largest observation.
  • Otherwise, an estimation of the number of (observations smaller than value + half the observations equal to value).

  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 added to the sketch.

  All values are -2 if the 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, quantile parsing errors, or incorrect number of arguments.

{{< /multitabs >}}