Welcome to Converto (pronounced convert-o, not conver-to); a simple measurement and unit conversion library for Python. This library is primarily an experiment in abusing operator overloading in classes to provide as literate a syntax as possible for moving between common measurement units.

Literate Conversion

This library is predicated on the idea that it's better to run across this in the middle of a source file:

# convert our running distance to centimeters
distance = 5 * miles * centimeters

Than this:

# convert our running distance to centimeters
distance = 5 * 160934.4

Or to work with time using sane combinations:

# determine how many days it's been since the last update
elapsedSeconds = 1000000
elapsedDays = elapsedSeconds * seconds * days

Converto can also help avoid mistakes when mixing different units in the same code:

# compare the different distances we collected
k = 15 * kilometers
m = 10 * miles

if m > k:
	# do something

Conversions

In it's current rudimentary form Converto supports the following units:

• Length

  • miles
  • feet
  • furlongs
  • Standard SI prefixes, from yoctometers (10 ^ -24) to yottameters (10 ^ 24)

• Time

  • seconds
  • minutes
  • hours
  • days

• Storage

  • SI prefixes (kilo, mega, giga, tera, peta, exa, zetta, yotta)
  • IEC prefixes (kibi, mebi, gibi, tebi, pebi, exbi, zebi, yobi)

• Temperature

  • Fahrenheit
  • Celsius
  • Kelvin
  • Rankine
  • Delisle
  • Newton
  • Reaumur
  • Romer

• Area

  • square_meters
  • square_feet

Examples

Create a basic measurement

from converto.length import miles

d = 5 * miles

# 5.00 miles
print d

Compare measurements in different units

from converto.length import miles, kilometers

m = 10 * miles
k = 15 * kilometers

if m > k:
	print "That's a lot of miles"

Modify a measurement

from converto.time import *

t = 10 * seconds * 6

# 60.00 seconds
print t

Convert between measurements

from converto.length import meters, miles

lap = 400 * meters
run = lap * 10 * miles

# 2.49 miles
print run

Get the value of a measurement. It's important to note that while len() and the size attribute can both be used to get the value of a measurement, the len() will always be rounded to an integer value. This is fine in some cases, but dangerous in others where the decimal portion of a measurement is meaningful.

from converto.time import days, seconds
from converto.length import miles, meters

d = 1 * days * seconds

# 86,400
print len(d)

l = 1 * miles * meters

# 1609.344
print l.size

Basic measurement math

from converto.length import feet, centimeters

s = ( 1 * feet ) - ( 10 * centimeters )

# 0.67 feet
print s

Shift between common measurements. The number shifted is not directly related to scale, but to the common sequence of units. Hence, shifting from meters to nanometers is 5 steps (meter > decimeter > centimeter > millimeter > micrometer > nanometer) not 9 (1 nanometer is 10 ^ -9 meters)

from converto.length import *

d = 5 * meters

# convert to kilometers
km = d << 3

# convert to nanometers
nm = d >> 5

Determine actual storage of a 1 terabyte harddrive:

from converto.storage import *

size = 1 * terabytes
actual = size * tebibytes

# 0.91 TiB
print actual

Move between measurement dimensions:

from converto.length import *
from converto.area import *

# determine size of an area by it's lengths
w = 1 * furlongs
h = 23 * centimeters

# determine the size in square feet (498.03 square feet)
a = (w * h) * square_feet

Roadmap

• add pow method to Measurements
  • add dimensional_pow to Measurements
• Volume Measurement
  • dimensional_* for Length, Area, and Volume relationships
• Add other dimensional shifts
  • division
  • roots
• Measurement relationships
  • area x length == volume
  • distance x time == speed
  • speed x time == acceleration
  • length and exponents
  • dimensional singleton to define combinations and result base measurements, rather than per-class overloading? Both?
    • Transitive mul, dimensioned pow, non-transitive div
• unit tests
• other operators
  • indexing as conversion/mapping
  • and/or/xor
  • power
  • i* ops (iadd, isub, etc)
  • divmod
  • binary ops
  • hash
  • repr
  • slicing
• add ConversionError and propogate it through the code to catch problems
• scaledmeasurement scaledmeasurement code path
• Single vs plural units, unit abbreviations
• Add compound units and multi-unit math via dimensional relationships
• Add chained units (convert a length into miles and feet, or a time into days, hours, minutes, and seconds)
• Examples, syntax changes
• Add other measurement units
  • improve time
  • force
  • weight
  • mass
  • speed
  • acceleration
  • pressure
  • torque