docs-v2/content/flux/v0/stdlib/math/ilogb.md

title	description	menu	weight
math.ilogb() function	`math.ilogb()` returns the binary exponent of `x` as an integer.	flux_v0_ref name parent identifier math.ilogb math math/ilogb	101

math.ilogb() returns the binary exponent of x as an integer.

Function type signature

(x: float) => int

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

Parameters

x

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

Examples

• Return the binary exponent of a value
• Use math.ilogb in map

Return the binary exponent of a value

import "math"

math.ilogb(x: 123.45)// 6

Use math.ilogb in map

import "sampledata"
import "math"

sampledata.float()
    |> map(fn: (r) => ({r with _value: math.ilogb(x: r._value)}))

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Input data

_time	*tag	_value
2021-01-01T00:00:00Z	t1	-2.18
2021-01-01T00:00:10Z	t1	10.92
2021-01-01T00:00:20Z	t1	7.35
2021-01-01T00:00:30Z	t1	17.53
2021-01-01T00:00:40Z	t1	15.23
2021-01-01T00:00:50Z	t1	4.43

_time	*tag	_value
2021-01-01T00:00:00Z	t2	19.85
2021-01-01T00:00:10Z	t2	4.97
2021-01-01T00:00:20Z	t2	-3.75
2021-01-01T00:00:30Z	t2	19.77
2021-01-01T00:00:40Z	t2	13.86
2021-01-01T00:00:50Z	t2	1.86

Output data

_time	_value	*tag
2021-01-01T00:00:00Z	1	t1
2021-01-01T00:00:10Z	3	t1
2021-01-01T00:00:20Z	2	t1
2021-01-01T00:00:30Z	4	t1
2021-01-01T00:00:40Z	3	t1
2021-01-01T00:00:50Z	2	t1

_time	_value	*tag
2021-01-01T00:00:00Z	4	t2
2021-01-01T00:00:10Z	2	t2
2021-01-01T00:00:20Z	1	t2
2021-01-01T00:00:30Z	4	t2
2021-01-01T00:00:40Z	3	t2
2021-01-01T00:00:50Z	0	t2

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