---
title: sample() function
description: >
  `sample()` selects a subset of the rows from each input table.
menu:
  flux_v0_ref:
    name: sample
    parent: universe
    identifier: universe/sample
weight: 101
flux/v0/tags: [transformations, selectors]
introduced: 0.7.0
---

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`sample()` selects a subset of the rows from each input table.

**Note:** `sample()` drops empty tables.

##### Function type signature

```js
(<-tables: stream[A], n: int, ?column: string, ?pos: int) => stream[A] where A: Record
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### n
({{< req >}})
Sample every Nth element.



### pos

Position offset from the start of results where sampling begins.
Default is -1 (random offset).

`pos` must be less than `n`. If pos is less than 0, a random offset is used.

### column

Column to operate on.



### tables

Input data. Default is piped-forward data (`<-`).




## Examples

### Sample every other result

```js
import "sampledata"

sampledata.int()
    |> sample(n: 2, pos: 1)

```

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{{% expand "View example input and output" %}}

#### Input data

| _time                | _value  | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:00Z | -2      | t1   |
| 2021-01-01T00:00:10Z | 10      | t1   |
| 2021-01-01T00:00:20Z | 7       | t1   |
| 2021-01-01T00:00:30Z | 17      | t1   |
| 2021-01-01T00:00:40Z | 15      | t1   |
| 2021-01-01T00:00:50Z | 4       | t1   |

| _time                | _value  | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:00Z | 19      | t2   |
| 2021-01-01T00:00:10Z | 4       | t2   |
| 2021-01-01T00:00:20Z | -3      | t2   |
| 2021-01-01T00:00:30Z | 19      | t2   |
| 2021-01-01T00:00:40Z | 13      | t2   |
| 2021-01-01T00:00:50Z | 1       | t2   |


#### Output data

| _time                | _value  | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:10Z | 10      | t1   |
| 2021-01-01T00:00:30Z | 17      | t1   |
| 2021-01-01T00:00:50Z | 4       | t1   |

| _time                | _value  | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:10Z | 4       | t2   |
| 2021-01-01T00:00:30Z | 19      | t2   |
| 2021-01-01T00:00:50Z | 1       | t2   |

{{% /expand %}}
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