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strings.substring() function

content/flux/v0/stdlib/strings/substring.md

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<!------------------------------------------------------------------------------ IMPORTANT: This page was generated from comments in the Flux source code. Any edits made directly to this page will be overwritten the next time the documentation is generated. To make updates to this documentation, update the function comments above the function definition in the Flux source code: https://github.com/influxdata/flux/blob/master/stdlib/strings/strings.flux#L834-L834 Contributing to Flux: https://github.com/influxdata/flux#contributing Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md ------------------------------------------------------------------------------->

strings.substring() returns a substring based on start and end parameters. These parameters are represent indices of UTF code points in the string.

When start or end are past the bounds of the string, respectively the start or end of the string is assumed. When end is less than or equal to start an empty string is returned.

Function type signature
js
(end: int, start: int, v: string) => string

{{% caption %}} For more information, see Function type signatures. {{% /caption %}}

Parameters

v

({{< req >}}) String value to search for.

start

({{< req >}}) Starting inclusive index of the substring.

end

({{< req >}}) Ending exclusive index of the substring.

Examples

Return part of a string based on character index

js
import "sampledata"
import "strings"

sampledata.string()
    |> map(fn: (r) => ({r with _value: strings.substring(v: r._value, start: 5, end: 9)}))

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

Input data

_time*tag_value
2021-01-01T00:00:00Zt1smpl_g9qczs
2021-01-01T00:00:10Zt1smpl_0mgv9n
2021-01-01T00:00:20Zt1smpl_phw664
2021-01-01T00:00:30Zt1smpl_guvzy4
2021-01-01T00:00:40Zt1smpl_5v3cce
2021-01-01T00:00:50Zt1smpl_s9fmgy
_time*tag_value
2021-01-01T00:00:00Zt2smpl_b5eida
2021-01-01T00:00:10Zt2smpl_eu4oxp
2021-01-01T00:00:20Zt2smpl_5g7tz4
2021-01-01T00:00:30Zt2smpl_sox1ut
2021-01-01T00:00:40Zt2smpl_wfm757
2021-01-01T00:00:50Zt2smpl_dtn2bv

Output data

_time_value*tag
2021-01-01T00:00:00Zg9qct1
2021-01-01T00:00:10Z0mgvt1
2021-01-01T00:00:20Zphw6t1
2021-01-01T00:00:30Zguvzt1
2021-01-01T00:00:40Z5v3ct1
2021-01-01T00:00:50Zs9fmt1
_time_value*tag
2021-01-01T00:00:00Zb5eit2
2021-01-01T00:00:10Zeu4ot2
2021-01-01T00:00:20Z5g7tt2
2021-01-01T00:00:30Zsox1t2
2021-01-01T00:00:40Zwfm7t2
2021-01-01T00:00:50Zdtn2t2

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