Work with floats

A float type represents a IEEE-754 64-bit floating-point number.

Type name: float

• Float syntax
• Convert data types to floats
• Operate on floats

Float syntax

A float literal contains a decimal integer, a decimal point, and a decimal fraction.

0.0
123.4
-123.456

• Scientific notation
• Infinity
• Not a Number (NaN)

Scientific notation

Flux does not support scientific notation float literal syntax. However, you can use float() to convert a scientific notation string into a float type.

1.23456e+78
// Error: error @1:8-1:9: undefined identifier e

float(v: "1.23456e+78")
// Returns 1.23456e+78 (float)

Infinity

Flux does not support infinite float literal syntax (+Inf and -Inf). However, you can use float() to convert a infinite string into a float type.

+Inf
// Error: error @1:2-1:5: undefined identifier Inf

float(v: "+Inf")
// Returns +Inf (float)

Not a Number

Flux does not support Not a Number (NaN) float literal syntax. However, you can use float() to convert a NaN string into a float type.

NaN
// Error: error @1:2-1:5: undefined identifier NaN

float(v: "NaN")
// Returns NaN (float)

Convert data types to floats

Use the float() function to convert the following basic types to floats:

• string: must be a numeric string or scientific notation
• bool: true converts to 1.0, false converts to 0.0
• int
• uint

float(v: "1.23")
// 1.23

float(v: true)
// Returns 1.0

float(v: 123)
// Returns 123.0

Convert columns to floats

Flux lets you iterate over rows in a stream of tables and convert columns to floats.

To convert the _value column to floats, use the toFloat() function.

data
    |> toFloat()

To convert any column to floats:

1. Use map() to iterate over and rewrite rows.
2. Use float() to convert columns values to floats.

data
    |> map(fn: (r) => ({ r with index: float(v: r.index) }))

Operate on floats

• Perform arithmetic operations on floats
• Compare float values
• Round float values
• Flux math package

Perform arithmetic operations on floats

To perform operations like adding, subtracting, multiplying, or dividing float values, use Flux arithmetic operators. Operands must be the same type.

1.23 + 45.67
// Returns 46.9

1.23 - 45.67
// Returns -44.440000000000005

float(v: "12345e+67") * 100.0
// Returns 1.2345000000000001e+73

144.0 / 12.0
// Returns 12.0

10.0 ^ 2.0
// Returns 100.0

Compare float values

Use Flux comparison operators to compare float values. Operands must be the same type. The operation returns a float.

12345600.0 == float(v: "1.23456e+07")
// Returns true

1.2 > -2.1
// Returns true

Round float values

1. Import the math package.
2. Use math.round() to round to the nearest whole number.

import "math"

math.round(x: 1.54)
// Returns 2.0

Flux math package

Use the math package to perform operations on float values.