content/flux/v0/stdlib/universe/count.md
count() returns the number of records in each input table.
The function counts both null and non-null records.
count() returns 0 for empty tables.
To keep empty tables in your data, set the following parameters for the
following functions:
| Function | Parameter |
|---|---|
filter() | onEmpty: "keep" |
window() | createEmpty: true |
aggregateWindow() | createEmpty: true |
(<-tables: stream[A], ?column: string) => stream[B] where A: Record, B: Record
{{% caption %}} For more information, see Function type signatures. {{% /caption %}}
Column to count values in and store the total count.
Input data. Default is piped-forward data (<-).
import "sampledata"
sampledata.string()
|> count()
filter() to filter data by the specific value you want to count.count() to count the number of rows in the table.import "sampledata"
data =
sampledata.int()
|> filter(fn: (r) => r._value > 10)
data
|> count()
{{< expand-wrapper >}} {{% expand "View example input and output" %}}
| _time | _value | *tag |
|---|---|---|
| 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:40Z | 15 | t1 |
| _time | _value | *tag |
|---|---|---|
| 2021-01-01T00:00:00Z | 19 | t2 |
| 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:40Z | 13 | t2 |
| *tag | _value |
|---|---|
| t1 | 2 |
| *tag | _value |
|---|---|
| t2 | 3 |
{{% /expand %}} {{< /expand-wrapper >}}