scaler

Introduction

This crate provides a convenient Formatter to scale, round, and display numbers.

Scaling describes the usage of decimal or binary unit prefixes to increase readability; though no scaling and scientific notation are also supported.
Rounding can be done either to a specified magnitude or to a number of significant digits.
Separators can be freely adjusted. The group separator separates groups of digits every 3 digits before the decimal separator, while the decimal separator separates the integer and fractional parts of a number.
The sign behaviour can be set to always show the sign, only show the sign when the number is negative, or never show the sign.

Usage

Execute Formatter::new to create a new Formatter with default settings.
Adjust separators, rounding, scaling, and sign behaviour as necessary using the setters.
Format numbers with Formatter::format.

`Rounding`

Magnitude:

Round to digit at magnitude $10^m$.
Contains $m$.

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::Magnitude(-2));
assert_eq!(f.format(123.456), "123,46");
assert_eq!(f.format(0.789), "790 m");
assert_eq!(f.format(42069), "42,06900 k");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::Magnitude(-1));
assert_eq!(f.format(123.456), "123,5");
assert_eq!(f.format(0.789), "800 m");
assert_eq!(f.format(42069), "42,0690 k");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::Magnitude(0));
assert_eq!(f.format(123.456), "123");
assert_eq!(f.format(0.789), "1");
assert_eq!(f.format(42069), "42,069 k");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::Magnitude(1));
assert_eq!(f.format(123.456), "120");
assert_eq!(f.format(0.789), "0");
assert_eq!(f.format(42069), "42,07 k");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::Magnitude(2));
assert_eq!(f.format(123.456), "100");
assert_eq!(f.format(0.789), "0");
assert_eq!(f.format(42069), "42,1 k");

SignificantDigits:

Round to $n$ significant numbers.
Contains $n$.

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::SignificantDigits(0));
assert_eq!(f.format(123.456), "0");
assert_eq!(f.format(0.789), "0");
assert_eq!(f.format(42069), "0");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::SignificantDigits(1));
assert_eq!(f.format(123.456), "100");
assert_eq!(f.format(0.789), "800 m");
assert_eq!(f.format(42069), "40 k");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::SignificantDigits(2));
assert_eq!(f.format(123.456), "120");
assert_eq!(f.format(0.789), "790 m");
assert_eq!(f.format(42069), "42 k");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::SignificantDigits(3));
assert_eq!(f.format(123.456), "123");
assert_eq!(f.format(0.789), "789 m");
assert_eq!(f.format(42069), "42,1 k");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::SignificantDigits(4));
assert_eq!(f.format(123.456), "123,5");
assert_eq!(f.format(0.789), "789,0 m");
assert_eq!(f.format(42069), "42,07 k");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_rounding(scaler::Rounding::SignificantDigits(5));
assert_eq!(f.format(123.456), "123,46");
assert_eq!(f.format(0.789), "789,00 m");
assert_eq!(f.format(42069), "42,069 k");

`Scaling`

Binary:

Scales by factor $2^(10) = 1.024$.
If no prefix for that magnitude defined: Fallback to scientific notation.
Contains whether or not to put space between number and unit prefix.

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::Binary(true));
assert_eq!(f.format(0.5), "1,000 * 2^(-1)");
assert_eq!(f.format(1), "1,000");
assert_eq!(f.format(64), "64,00");
assert_eq!(f.format(128), "128,0");
assert_eq!(f.format(1023), "1.023");
assert_eq!(f.format(1024), "1,000 Ki");
assert_eq!(f.format(2_f64.powi(10)), "1,000 Ki");
assert_eq!(f.format(2_f64.powi(20)), "1,000 Mi");
assert_eq!(f.format(2_f64.powi(30)), "1,000 Gi");
assert_eq!(f.format(2_f64.powi(40)), "1,000 Ti");
assert_eq!(f.format(2_f64.powi(50)), "1,000 Pi");
assert_eq!(f.format(2_f64.powi(60)), "1,000 Ei");
assert_eq!(f.format(2_f64.powi(70)), "1,000 Zi");
assert_eq!(f.format(2_f64.powi(80)), "1,000 Yi");
assert_eq!(f.format(2_f64.powi(90)), "1,000 * 2^(90)");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::Binary(false));
assert_eq!(f.format(1024), "1,000Ki");

Decimal:

Scales by factor $10^(3) = 1.000$.
If no prefix for that magnitude defined: Fallback to scientific notation.
Contains whether or not to put space between number and unit prefix.

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::Decimal(true));
assert_eq!(f.format(1e-31), "1,000 * 10^(-31)");
assert_eq!(f.format(1e-30), "1,000 q");
assert_eq!(f.format(1e-27), "1,000 r");
assert_eq!(f.format(1e-24), "1,000 y");
assert_eq!(f.format(1e-21), "1,000 z");
assert_eq!(f.format(1e-18), "1,000 a");
assert_eq!(f.format(1e-15), "1,000 f");
assert_eq!(f.format(1e-12), "1,000 p");
assert_eq!(f.format(1e-9), "1,000 n");
assert_eq!(f.format(1e-6), "1,000 µ");
assert_eq!(f.format(1e-3), "1,000 m");
assert_eq!(f.format(1), "1,000");
assert_eq!(f.format(10), "10,00");
assert_eq!(f.format(100), "100,0");
assert_eq!(f.format(999), "999,0");
assert_eq!(f.format(1000), "1,000 k");
assert_eq!(f.format(1e3), "1,000 k");
assert_eq!(f.format(1e6), "1,000 M");
assert_eq!(f.format(1e9), "1,000 G");
assert_eq!(f.format(1e12), "1,000 T");
assert_eq!(f.format(1e15), "1,000 P");
assert_eq!(f.format(1e18), "1,000 E");
assert_eq!(f.format(1e21), "1,000 Z");
assert_eq!(f.format(1e24), "1,000 Y");
assert_eq!(f.format(1e27), "1,000 R");
assert_eq!(f.format(1e30), "1,000 Q");
assert_eq!(f.format(1e33), "1,000 * 10^(33)");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::Decimal(false));
assert_eq!(f.format(1000), "1,000k");

None:

no scaling
no fallback to scientific notation

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::None);
assert_eq!(f.format(1e-10), "0,0000000001000");
assert_eq!(f.format(0.1), "0,1000");
assert_eq!(f.format(1), "1,000");
assert_eq!(f.format(10), "10,00");
assert_eq!(f.format(100), "100,0");
assert_eq!(f.format(1000), "1.000");
assert_eq!(f.format(1e10), "10.000.000.000");

Scientific:

always scientific notation

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::Scientific);
assert_eq!(f.format(0.1), "1,000 * 10^(-1)");
assert_eq!(f.format(1), "1,000 * 10^(0)");
assert_eq!(f.format(10), "1,000 * 10^(1)");

Separators

group_separator
- Separates groups every 3 digits before the decimal separator.
decimal_separator
- Separates the integer and fractional parts of a number.

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::None)
    .set_separators(".", ",");
assert_eq!(f.format(1), "1,000");
assert_eq!(f.format(10), "10,00");
assert_eq!(f.format(100), "100,0");
assert_eq!(f.format(1000), "1.000");
assert_eq!(f.format(10000), "10.000");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::None)
    .set_separators("", ",");
assert_eq!(f.format(1), "1,000");
assert_eq!(f.format(10), "10,00");
assert_eq!(f.format(100), "100,0");
assert_eq!(f.format(1000), "1000");
assert_eq!(f.format(10000), "10000");

let f: scaler::Formatter = scaler::Formatter::new()
    .set_scaling(scaler::Scaling::None)
    .set_separators(",", ".");
assert_eq!(f.format(1), "1.000");
assert_eq!(f.format(10), "10.00");
assert_eq!(f.format(100), "100.0");
assert_eq!(f.format(1000), "1,000");
assert_eq!(f.format(10000), "10,000");

`Sign`

Always

Always show sign, even when number is positive.

let f: scaler::Formatter = scaler::Formatter::new()
    .set_sign(scaler::Sign::Always);
assert_eq!(f.format(std::f64::NEG_INFINITY), "-∞");
assert_eq!(f.format(-1), "-1,000");
assert_eq!(f.format(0), "+0,000");
assert_eq!(f.format(1), "+1,000");
assert_eq!(f.format(std::f64::INFINITY), "+∞");

OnlyMinus

Only show sign when number is negative.

let f: scaler::Formatter = scaler::Formatter::new()
    .set_sign(scaler::Sign::OnlyMinus);
assert_eq!(f.format(std::f64::NEG_INFINITY), "-∞");
assert_eq!(f.format(-1), "-1,000");
assert_eq!(f.format(0), "0,000");
assert_eq!(f.format(1), "1,000");
assert_eq!(f.format(std::f64::INFINITY), "∞");

scaler 1.0.3