docs-v2/content/flux/v0/stdlib/strings/strlen.md

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---
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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To make updates to this documentation, update the function comments above the
function definition in the Flux source code:
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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 >}}