109 lines
2.3 KiB
Markdown
109 lines
2.3 KiB
Markdown
---
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title: math.copysign() function
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description: >
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`math.copysign()` returns a value with the magnitude `x` and the sign of `y`.
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menu:
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flux_v0_ref:
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name: math.copysign
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parent: math
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identifier: math/copysign
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weight: 101
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---
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<!------------------------------------------------------------------------------
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IMPORTANT: This page was generated from comments in the Flux source code. Any
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edits made directly to this page will be overwritten the next time the
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documentation is generated.
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To make updates to this documentation, update the function comments above the
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function definition in the Flux source code:
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https://github.com/influxdata/flux/blob/master/stdlib/math/math.flux#L465-L465
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Contributing to Flux: https://github.com/influxdata/flux#contributing
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Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md
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------------------------------------------------------------------------------->
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`math.copysign()` returns a value with the magnitude `x` and the sign of `y`.
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##### Function type signature
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```js
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(x: float, y: float) => float
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```
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{{% caption %}}
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For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
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{{% /caption %}}
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## Parameters
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### x
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({{< req >}})
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Magnitude to use in the operation.
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### y
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({{< req >}})
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Sign to use in the operation.
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## Examples
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- [Return the copysign of two columns](#return-the-copysign-of-two-columns)
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- [Use math.copysign in map](#use-mathcopysign-in-map)
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### Return the copysign of two columns
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```js
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import "math"
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math.copysign(x: 1.0, y: 2.0)
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```
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### Use math.copysign in map
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```js
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import "math"
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data
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|> map(fn: (r) => ({_time: r._time, _value: math.copysign(x: r.x, y: r.y)}))
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```
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{{< expand-wrapper >}}
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{{% expand "View example input and output" %}}
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#### Input data
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| _time | x | y |
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| -------------------- | --- | ---- |
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| 2021-01-01T00:00:00Z | 1.2 | 3.9 |
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| 2021-01-01T01:00:00Z | 2.4 | -4.2 |
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| 2021-01-01T02:00:00Z | 3.6 | 5.3 |
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| 2021-01-01T03:00:00Z | 4.8 | -6.8 |
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| 2021-01-01T04:00:00Z | 5.1 | 7.5 |
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#### Output data
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| _time | _value |
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| -------------------- | ------ |
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| 2021-01-01T00:00:00Z | 1.2 |
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| 2021-01-01T01:00:00Z | -2.4 |
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| 2021-01-01T02:00:00Z | 3.6 |
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| 2021-01-01T03:00:00Z | -4.8 |
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| 2021-01-01T04:00:00Z | 5.1 |
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{{% /expand %}}
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{{< /expand-wrapper >}}
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