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math.isNaN() function

content/flux/v0/stdlib/math/isnan.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/math/math.flux#L1159-L1159 Contributing to Flux: https://github.com/influxdata/flux#contributing Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md ------------------------------------------------------------------------------->

math.isNaN() reports whether f is an IEEE 754 "not-a-number" value.

Function type signature
js
(f: float) => bool

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

Parameters

f

({{< req >}}) Value to operate on.

Examples

Check if a value is a NaN float value

js
import "math"

math.isNaN(f: 12.345)// false


Use math.isNaN in map

js
import "math"

data
    |> map(fn: (r) => ({r with _value: math.isNaN(f: r._value)}))

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

Input data

_time*tag_value
2021-01-01T00:00:00Zt1-2.18
2021-01-01T00:00:10Zt1NaN
2021-01-01T00:00:20Zt17.35
2021-01-01T00:00:30Zt1NaN
2021-01-01T00:00:40Zt1NaN
2021-01-01T00:00:50Zt14.43
_time*tag_value
2021-01-01T00:00:00Zt2NaN
2021-01-01T00:00:10Zt24.97
2021-01-01T00:00:20Zt2-3.75
2021-01-01T00:00:30Zt219.77
2021-01-01T00:00:40Zt2NaN
2021-01-01T00:00:50Zt21.86

Output data

_time_value*tag
2021-01-01T00:00:00Zfalset1
2021-01-01T00:00:10Ztruet1
2021-01-01T00:00:20Zfalset1
2021-01-01T00:00:30Ztruet1
2021-01-01T00:00:40Ztruet1
2021-01-01T00:00:50Zfalset1
_time_value*tag
2021-01-01T00:00:00Ztruet2
2021-01-01T00:00:10Zfalset2
2021-01-01T00:00:20Zfalset2
2021-01-01T00:00:30Zfalset2
2021-01-01T00:00:40Ztruet2
2021-01-01T00:00:50Zfalset2

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