content/enterprise_influxdb/v1/flux/guides/fill.md
Use the fill() function
to replace null values with:
data
|> fill(usePrevious: true)
// OR
data
|> fill(value: 0.0)
{{% note %}}
The fill() function does not fill empty windows of time.
It only replaces null values in existing data.
Filling empty windows of time requires time interpolation
(see influxdata/flux#2428).
{{% /note %}}
To fill null values with the previous non-null value, set the usePrevious parameter to true.
{{% note %}} Values remain null if there is no previous non-null value in the table. {{% /note %}}
data
|> fill(usePrevious: true)
{{< flex >}} {{% flex-content %}} Given the following input:
| _time | _value |
|---|---|
| 2020-01-01T00:01:00Z | null |
| 2020-01-01T00:02:00Z | 0.8 |
| 2020-01-01T00:03:00Z | null |
| 2020-01-01T00:04:00Z | null |
| 2020-01-01T00:05:00Z | 1.4 |
| {{% /flex-content %}} | |
| {{% flex-content %}} | |
fill(usePrevious: true) returns: |
| _time | _value |
|---|---|
| 2020-01-01T00:01:00Z | null |
| 2020-01-01T00:02:00Z | 0.8 |
| 2020-01-01T00:03:00Z | 0.8 |
| 2020-01-01T00:04:00Z | 0.8 |
| 2020-01-01T00:05:00Z | 1.4 |
| {{% /flex-content %}} | |
| {{< /flex >}} |
To fill null values with a specified value, use the value parameter to specify the fill value.
The fill value must match the data type
of the column.
data
|> fill(value: 0.0)
{{< flex >}} {{% flex-content %}} Given the following input:
| _time | _value |
|---|---|
| 2020-01-01T00:01:00Z | null |
| 2020-01-01T00:02:00Z | 0.8 |
| 2020-01-01T00:03:00Z | null |
| 2020-01-01T00:04:00Z | null |
| 2020-01-01T00:05:00Z | 1.4 |
| {{% /flex-content %}} | |
| {{% flex-content %}} | |
fill(value: 0.0) returns: |
| _time | _value |
|---|---|
| 2020-01-01T00:01:00Z | 0.0 |
| 2020-01-01T00:02:00Z | 0.8 |
| 2020-01-01T00:03:00Z | 0.0 |
| 2020-01-01T00:04:00Z | 0.0 |
| 2020-01-01T00:05:00Z | 1.4 |
| {{% /flex-content %}} | |
| {{< /flex >}} |