---
title: types.isType() function
description: types.isType() tests if a value is a specified type.
url: https://docs.influxdata.com/flux/v0/stdlib/types/istype/
estimated_tokens: 2959
product: Flux
version: v0
publisher: InfluxData
canonical: https://docs.influxdata.com/flux/v0/stdlib/types/istype/
date: '2024-04-08T16:01:02-06:00'
lastmod: '2024-04-08T16:01:02-06:00'
---

* Flux 0.141.0+

InfluxDB support

`types.isType()` tests if a value is a specified type.

##### Function type signature

```js
(type: string, v: A) => bool where A: Basic
```

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

## Parameters

### v

(Required)
Value to test.

### type

(Required)
String describing the type to check against.

**Supported types**:

* string
* bytes
* int
* uint
* float
* bool
* time
* duration
* regexp

## Examples

* [Filter by value type](#filter-by-value-type)
* [Aggregate or select data based on type](#aggregate-or-select-data-based-on-type)

### Filter by value type

```js
import "types"

data
    |> filter(fn: (r) => types.isType(v: r._value, type: "string"))
```

[](#view-example-input-and-output)

View example input and output

#### Input data

|       \_time       |\*\_field|\_value|
|--------------------|---------|-------|
|2022-01-01T00:00:00Z|   foo   |  12   |
|2022-01-01T00:01:00Z|   foo   |  15   |
|2022-01-01T00:02:00Z|   foo   |   9   |

|\_time|\*\_field|\_value|
|------|---------|-------|

|       \_time       |\*\_field|\_value |
|--------------------|---------|--------|
|2022-01-01T00:00:00Z|   bar   |0jCcsMYM|
|2022-01-01T00:01:00Z|   bar   |jHvuDw35|
|2022-01-01T00:02:00Z|   bar   |HE5uCIC2|

#### Output data

|       \_time       |\*\_field|\_value |
|--------------------|---------|--------|
|2022-01-01T00:00:00Z|   bar   |0jCcsMYM|
|2022-01-01T00:01:00Z|   bar   |jHvuDw35|
|2022-01-01T00:02:00Z|   bar   |HE5uCIC2|

### Aggregate or select data based on type

```js
import "types"

nonNumericData =
    data
        |> filter(
            fn: (r) =>
                types.isType(v: r._value, type: "string") or types.isType(
                        v: r._value,
                        type: "bool",
                    ),
        )
        |> aggregateWindow(every: 30s, fn: last)

numericData =
    data
        |> filter(
            fn: (r) =>
                types.isType(v: r._value, type: "int") or types.isType(v: r._value, type: "float"),
        )
        |> aggregateWindow(every: 30s, fn: mean)

union(tables: [nonNumericData, numericData])
```

[](#view-example-input-and-output)

View example input and output

#### Input data

|     \*\_start      |      \*\_stop      |       \_time       |\*type|\_value|
|--------------------|--------------------|--------------------|------|-------|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:00Z| bool | true  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:10Z| bool | true  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:20Z| bool | false |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:30Z| bool | true  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:40Z| bool | false |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:50Z| bool | false |

|\*\_start|\*\_stop|\_time|\*type|\_value|
|---------|--------|------|------|-------|

|     \*\_start      |      \*\_stop      |       \_time       |\*type|\_value|
|--------------------|--------------------|--------------------|------|-------|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:00Z|float |\-2.18 |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:10Z|float | 10.92 |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:20Z|float | 7.35  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:30Z|float | 17.53 |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:40Z|float | 15.23 |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:50Z|float | 4.43  |

|\*\_start|\*\_stop|\_time|\_value|\*type|
|---------|--------|------|-------|------|

|     \*\_start      |      \*\_stop      |       \_time       |\_value|\*type|
|--------------------|--------------------|--------------------|-------|------|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:00Z|  \-2  | int  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:10Z|  10   | int  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:20Z|   7   | int  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:30Z|  17   | int  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:40Z|  15   | int  |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:50Z|   4   | int  |

|\*\_start|\*\_stop|\_time|\*type|\_value|
|---------|--------|------|------|-------|

|     \*\_start      |      \*\_stop      |       \_time       |\*type|  \_value   |
|--------------------|--------------------|--------------------|------|------------|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:00Z|string|smpl\_g9qczs|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:10Z|string|smpl\_0mgv9n|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:20Z|string|smpl\_phw664|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:30Z|string|smpl\_guvzy4|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:40Z|string|smpl\_5v3cce|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:50Z|string|smpl\_s9fmgy|

#### Output data

|     \*\_start      |      \*\_stop      |       \_time       |\*type|\_value|
|--------------------|--------------------|--------------------|------|-------|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:30Z| bool | false |
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:01:00Z| bool | false |

|\_time|\*\_start|\*\_stop|\*type|\_value|
|------|---------|--------|------|-------|

|       \_time       |     \*\_start      |      \*\_stop      |\*type|     \_value      |
|--------------------|--------------------|--------------------|------|------------------|
|2021-01-01T00:00:30Z|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|float |5.363333333333333 |
|2021-01-01T00:01:00Z|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|float |12.396666666666668|

|       \_time       |     \*\_start      |      \*\_stop      |\*type|\_value|
|--------------------|--------------------|--------------------|------|-------|
|2021-01-01T00:00:30Z|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z| int  |   5   |
|2021-01-01T00:01:00Z|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z| int  |  12   |

|\*\_start|\*\_stop|\_time|\*type|\_value|
|---------|--------|------|------|-------|

|     \*\_start      |      \*\_stop      |       \_time       |\*type|  \_value   |
|--------------------|--------------------|--------------------|------|------------|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:00:30Z|string|smpl\_phw664|
|2021-01-01T00:00:00Z|2021-01-01T00:01:00Z|2021-01-01T00:01:00Z|string|smpl\_s9fmgy|

[types](/flux/v0/tags/types/)[tests](/flux/v0/tags/tests/)
| _time | *_field | _value |
| --- | --- | --- |
| _time | *_field | _value |
| 2022-01-01T00:00:00Z | foo | 12 |
| 2022-01-01T00:01:00Z | foo | 15 |
| 2022-01-01T00:02:00Z | foo | 9 |

| _time | *_field | _value |
| --- | --- | --- |
| _time | *_field | _value |

| _time | *_field | _value |
| --- | --- | --- |
| _time | *_field | _value |
| 2022-01-01T00:00:00Z | bar | 0jCcsMYM |
| 2022-01-01T00:01:00Z | bar | jHvuDw35 |
| 2022-01-01T00:02:00Z | bar | HE5uCIC2 |

| _time | *_field | _value |
| --- | --- | --- |
| _time | *_field | _value |
| 2022-01-01T00:00:00Z | bar | 0jCcsMYM |
| 2022-01-01T00:01:00Z | bar | jHvuDw35 |
| 2022-01-01T00:02:00Z | bar | HE5uCIC2 |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | *type | _value |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | bool | true |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | bool | true |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | bool | false |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | bool | true |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | bool | false |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | bool | false |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | *type | _value |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | *type | _value |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | float | -2.18 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | float | 10.92 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | float | 7.35 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | float | 17.53 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | float | 15.23 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | float | 4.43 |

| *_start | *_stop | _time | _value | *type |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | _value | *type |

| *_start | *_stop | _time | _value | *type |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | _value | *type |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | -2 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 10 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | 7 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 17 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 15 | int |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | int |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | *type | _value |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | *type | _value |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | string | smpl_g9qczs |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | string | smpl_0mgv9n |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | string | smpl_phw664 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | string | smpl_guvzy4 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | string | smpl_5v3cce |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | string | smpl_s9fmgy |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | *type | _value |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | bool | false |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:01:00Z | bool | false |

| _time | *_start | *_stop | *type | _value |
| --- | --- | --- | --- | --- |
| _time | *_start | *_stop | *type | _value |

| _time | *_start | *_stop | *type | _value |
| --- | --- | --- | --- | --- |
| _time | *_start | *_stop | *type | _value |
| 2021-01-01T00:00:30Z | 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | float | 5.363333333333333 |
| 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | float | 12.396666666666668 |

| _time | *_start | *_stop | *type | _value |
| --- | --- | --- | --- | --- |
| _time | *_start | *_stop | *type | _value |
| 2021-01-01T00:00:30Z | 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | int | 5 |
| 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | int | 12 |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | *type | _value |

| *_start | *_stop | _time | *type | _value |
| --- | --- | --- | --- | --- |
| *_start | *_stop | _time | *type | _value |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | string | smpl_phw664 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:01:00Z | string | smpl_s9fmgy |