52 lines
1.1 KiB
Markdown
52 lines
1.1 KiB
Markdown
---
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title: strings.index() function
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description: >
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The strings.index() function returns the index of the first instance of a substring
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in another string.
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aliases:
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- /influxdb/v2.0/reference/flux/functions/strings/index-func/
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- /influxdb/v2.0/reference/flux/stdlib/strings/index-func/
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- /influxdb/cloud/reference/flux/stdlib/strings/index-func/
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menu:
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flux_0_x_ref:
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name: strings.index
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parent: strings
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weight: 301
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related:
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- /flux/v0.x/stdlib/strings/indexany/
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- /flux/v0.x/stdlib/strings/lastindex/
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- /flux/v0.x/stdlib/strings/lastindexany/
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introduced: 0.18.0
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---
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The `strings.index()` function returns the index of the first instance of a substring
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in a string. If the substring is not present, it returns `-1`.
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_**Output data type:** Integer_
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```js
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import "strings"
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strings.index(v: "go gopher", substr: "go")
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// returns 0
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```
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## Parameters
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### v {data-type="string"}
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The string value to search.
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### substr {data-type="string"}
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The substring to search for.
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## Examples
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###### Find the first occurrence of a substring
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```js
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import "strings"
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data
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|> map(fn: (r) => ({r with the_index: strings.index(v: r.pageTitle, substr: "the")}))
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```
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