Supported Exponent Replacements

sciform offers exponent replacement modes which provide translations between exponent strings and conventional alphabetic symbol representations. For decimal exponents in engineering formats, SI prefix translations are available according to the SI prefixes. It is also possible to convert decimal exponents into parts-per notation. For binary formats, the IEC prefix translations are available matched to integer multiples of 10 according to the IEC prefixes.

SI Prefixes

SI Prefixes
Exponent Value	Prefix Name	Prefix
10⁺³⁰	Quetta	Q
10⁺²⁷	Ronna	R
10⁺²⁴	Yotta	Y
10⁺²¹	Zetta	Z
10⁺¹⁸	Exa	E
10⁺¹⁵	Peta	P
10⁺¹²	Tera	T
10⁺⁹	Giga	G
10⁺⁶	Mega	M
10⁺³	kilo	k
10^-3	milli	m
10^-6	micro	µ
10^-9	nano	n
10^-12	pico	p
10^-15	femto	f
10^-18	atto	a
10^-21	zepto	z
10^-24	yocto	y
10^-27	ronto	r
10^-30	quecto	q

Extra SI Prefixes

The user can additionally add the following extra si prefixes using the Extra Exponent Replacements options:

Extra SI Prefixes
Exponent Value	Prefix Name	Prefix
10⁺²	hecto	h
10⁺¹	deca	da
10^-1	deci	d
10^-2	centi	c

Parts Per Forms

Parts Per Forms
Exponent Value	Prefix Name	Prefix
10⁰	unity	`no symbol`
10^-6	parts-per-million	ppm
10^-9	parts-per-billion	ppb
10^-12	parts-per-trillion	ppt
10^-15	parts-per-quadrillion	ppq

The user can additionally add a parts-per-thousand form ppth corresponding to 10^-3 using the add_ppth_form option. Note that the definitions here conform to the short scale naming convention for large numbers, but that some locales use the long scale naming convention for large numbers. These two scales disagree on the numerical values for terms like “billion” and “trillion”. For this reason, the usage of this notation is sometimes discouraged. Note that it is possible, using the extra_parts_per_forms option to override the standard mappings listed above.

>>> from sciform import Formatter
>>> formatter = Formatter(
...     exp_mode="engineering",
...     exp_format="parts_per",
...     extra_parts_per_forms={-9: None, -12: "ppb"},
... )
>>> print(formatter(33e-9))
33e-09
>>> print(formatter(33e-12))
33 ppb

IEC Prefixes

IEC Prefixes
Exponent Value	Prefix Name	Prefix
2⁺⁸⁰	yobi	Yi
2⁺⁷⁰	zebi	Zi
2⁺⁶⁰	exi	Ei
2⁺⁵⁰	pebi	Pi
2⁺⁴⁰	tebi	Ti
2⁺³⁰	gibi	Gi
2⁺²⁰	mebi	Mi
2⁺¹⁰	kibi	Ki