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Description:

prefixed 0.9.0

Overview
Prefixed provides an alternative implementation of the built-in float which supports
formatted output with SI (decimal) and IEC (binary) prefixes.
>>> from prefixed import Float

>>> f'{Float(3250):.2h}'
'3.25k'

>>> '{:.2h}s'.format(Float(.00001534))
'15.34μs'

>>> '{:.2k}B'.format(Float(42467328))
'40.50MiB'

>>> f'{Float(2048):.2m}B'
'2.00KB'
Because prefixed.Float inherits from the built-in float, it behaves
exactly the same in most cases.
When a math operation is performed with another real number type
(float, int), the result will be a prefixed.Float instance.

Presentation Types
Additional presentation types 'h', 'H', 'k', 'K',
'm', and 'M' are supported for f-strings and format().

Type
Meaning

'h'
SI format. Outputs the number with closest divisible SI prefix.
(k, M, G, …)

'H'
Same as 'h' with precision indicating significant digits.

'k'
IEC Format. Outputs the number with closest divisible IEC prefix.
(Ki, Mi, Gi, …)

'K'
Same as 'k' with precision indicating significant digits.

'm'
Short IEC Format. Same as 'k' but only a single character.
(K, M, G, …)

'M'
Same as 'm' with precision indicating significant digits.

'j'
Alias for 'k' - DEPRECATED

'J'
Alias for 'm' - DEPRECATED

String Initialization
When initializing from strings, SI and IEC prefixes are honored
>>> Float('2k')
Float(2000.0)

>>> Float('2Ki')
Float(2048.0)

Additional Flags
An additional format flag ‘!’ is available which adds a space before the prefix
>>> f'{Float(3250):!.2h}'
'3.25 k'

Significant Digits
When the 'H', 'K, or 'M' presentation types are used, precision is treated as
the number of significant digits to include. Standard rounding will occur for the final digit.
>>> f'{Float(1246):.3h}'
'1.246k'

>>> f'{Float(1246):.3H}'
'1.25k'
By default, trailing zeros are removed.
>>> f'{Float(1000):.3H}'
'1k'
To preserve trailing zeros, include the '#' flag.
>>> f'{Float(1000):#.3H}'
'1.00k'

Adjustable Thresholds
An additional field, margin, can be specified which lowers or raises the threshold for
for each prefix by the given percentage.
Margin is specified before precision with the syntax %[-]digit+.
>>> f'{Float(950):.2h}'
'950.00'

>>> f'{Float(950):%-5.2h}'
'0.95k'

>>> f'{Float(1000):%5.2h}'
'1000.00'

>>> f'{Float(1050):%5.2h}'
'1.05k'

Supported Prefixes

SI (Decimal) Prefixes

Prefix
Name
Base

Q
Quetta
1030

R
Ronna
1027

Y
Yotta
1024

Z
Zetta
1021

E
Exa
1018

P
Peta
1015

T
Tera
1012

G
Giga
109

M
Mega
106

k
Kilo
103

m
Milli
10-3

μ
Micro
10-6

n
Nano
10-9

p
Pico
10-12

f
Femto
10-15

a
Atto
10-18

z
Zepto
10-21

y
Yocto
10-24

r
Ronto
10-27

q
Quecto
10-30

Note
Prefixed uses the lowercase Greek letter mu (‘μ’), U+03BC, to represent the Micro
prefix, but will accept input using the Micro sign (‘µ’), U+00B5. This complies
with the preference defined in Unicode Technical Report #25 section 2.5.

IEC (Binary) Prefixes

Prefix
Name
Base

Y
Yobi
280

Z
Zebi
270

E
Exbi
260

P
Pedi
250

T
Tebi
240

G
Gibi
230

M
Mebi
220

K
Kibi
210