---
title: strings.strlen() function
description: >
  `strings.strlen()` returns the length of a string. String length is determined by the number of UTF code points a string contains.
menu:
  flux_v0_ref:
    name: strings.strlen
    parent: strings
    identifier: strings/strlen
weight: 101
---

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`strings.strlen()` returns the length of a string. String length is determined by the number of UTF code points a string contains.



##### Function type signature

```js
(v: string) => int
```

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

## Parameters

### v
({{< req >}})
String value to measure.




## Examples

- [Filter based on string value length](#filter-based-on-string-value-length)
- [Store the length of string values](#store-the-length-of-string-values)

### Filter based on string value length

```js
import "strings"

data
    |> filter(fn: (r) => strings.strlen(v: r._value) <= 6)

```

{{< expand-wrapper >}}
{{% expand "View example input and output" %}}

#### Input data

| _time                | _value   | *tag |
| -------------------- | -------- | ---- |
| 2021-01-01T00:00:00Z | pl_gqcz  | t1   |
| 2021-01-01T00:00:10Z | pl_gvn   | t1   |
| 2021-01-01T00:00:20Z | pl_phw   | t1   |
| 2021-01-01T00:00:30Z | pl_guvzy | t1   |
| 2021-01-01T00:00:40Z | pl_vcce  | t1   |
| 2021-01-01T00:00:50Z | pl_fgy   | t1   |

| _time                | _value   | *tag |
| -------------------- | -------- | ---- |
| 2021-01-01T00:00:00Z | pl_beida | t2   |
| 2021-01-01T00:00:10Z | pl_euoxp | t2   |
| 2021-01-01T00:00:20Z | pl_gtz   | t2   |
| 2021-01-01T00:00:30Z | pl_oxut  | t2   |
| 2021-01-01T00:00:40Z | pl_wf    | t2   |
| 2021-01-01T00:00:50Z | pl_dtnbv | t2   |


#### Output data

| _time                | _value  | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:10Z | pl_gvn  | t1   |
| 2021-01-01T00:00:20Z | pl_phw  | t1   |
| 2021-01-01T00:00:50Z | pl_fgy  | t1   |

| _time                | _value  | *tag |
| -------------------- | ------- | ---- |
| 2021-01-01T00:00:20Z | pl_gtz  | t2   |
| 2021-01-01T00:00:40Z | pl_wf   | t2   |

{{% /expand %}}
{{< /expand-wrapper >}}

### Store the length of string values

```js
import "strings"

data
    |> map(fn: (r) => ({r with length: strings.strlen(v: r._value)}))

```

{{< expand-wrapper >}}
{{% expand "View example input and output" %}}

#### Input data

| _time                | _value   | *tag |
| -------------------- | -------- | ---- |
| 2021-01-01T00:00:00Z | pl_gqcz  | t1   |
| 2021-01-01T00:00:10Z | pl_gvn   | t1   |
| 2021-01-01T00:00:20Z | pl_phw   | t1   |
| 2021-01-01T00:00:30Z | pl_guvzy | t1   |
| 2021-01-01T00:00:40Z | pl_vcce  | t1   |
| 2021-01-01T00:00:50Z | pl_fgy   | t1   |

| _time                | _value   | *tag |
| -------------------- | -------- | ---- |
| 2021-01-01T00:00:00Z | pl_beida | t2   |
| 2021-01-01T00:00:10Z | pl_euoxp | t2   |
| 2021-01-01T00:00:20Z | pl_gtz   | t2   |
| 2021-01-01T00:00:30Z | pl_oxut  | t2   |
| 2021-01-01T00:00:40Z | pl_wf    | t2   |
| 2021-01-01T00:00:50Z | pl_dtnbv | t2   |


#### Output data

| _time                | _value   | length  | *tag |
| -------------------- | -------- | ------- | ---- |
| 2021-01-01T00:00:00Z | pl_gqcz  | 7       | t1   |
| 2021-01-01T00:00:10Z | pl_gvn   | 6       | t1   |
| 2021-01-01T00:00:20Z | pl_phw   | 6       | t1   |
| 2021-01-01T00:00:30Z | pl_guvzy | 8       | t1   |
| 2021-01-01T00:00:40Z | pl_vcce  | 7       | t1   |
| 2021-01-01T00:00:50Z | pl_fgy   | 6       | t1   |

| _time                | _value   | length  | *tag |
| -------------------- | -------- | ------- | ---- |
| 2021-01-01T00:00:00Z | pl_beida | 8       | t2   |
| 2021-01-01T00:00:10Z | pl_euoxp | 8       | t2   |
| 2021-01-01T00:00:20Z | pl_gtz   | 6       | t2   |
| 2021-01-01T00:00:30Z | pl_oxut  | 7       | t2   |
| 2021-01-01T00:00:40Z | pl_wf    | 5       | t2   |
| 2021-01-01T00:00:50Z | pl_dtnbv | 8       | t2   |

{{% /expand %}}
{{< /expand-wrapper >}}