Unit Interpreter

This function will try its best to interpret strings like "liter/(nmol ms)" rules: 1. only one slash is allowed 2. M can be mega or mol/l: writing M for molarity will treat molarity as it's own unit kind; writing "molarity" will be translated into two SI units (mol and litre) 3. prefixes and units can be words or single letters 4. everything after a slash is the denominator 5. u is an accepted replacement for \(\\mu\) (unicode Greek mu or unicode micro symbol) 6. no parentheses (ignored): "(m/s)*kg" will be misinterpreted

Usage

unit.from.string(unit.str)

Arguments

unit.str

a string that contains a human readable unit

Value

data.frame with an interpretation of the unit (multiplier is unused here, but may be used later to deal with units such as hours (kind=second, multiplier=60)

Details

this returns a data.frame with components as in the sbml standard: kind, multiplier, scale and exponent since there is only one slash,parentheses do nothing everything after a slash is the denominator, so: l/mol s is the same as (l)/(mol s) Remark: not all units are understood.

Examples

print(unit.from.string("m/s"))
#> «m/s» has been interpreted as
#> the product of: 
#>                        m_per_s
#> ==============================
#> (1 × metre × 10^(0))^(1)
#> (1 × second × 10^(0))^(-1)
print(unit.from.string("micromolarity"))
#> «micromolarity» has been interpreted as
#> the product of: 
#>                  micromolarity
#> ==============================
#> (1 × mole × 10^(-6))^(1)
#> (1 × litre × 10^(0))^(-1)
print(unit.from.string("µM"))
#> «µM» has been interpreted as
#> the product of: 
#>                            µM
#> ==============================
#> (1 × mole × 10^(-6))^(1)
#> (1 × litre × 10^(0))^(-1)