NEWS in package ‘units’

Changes in version 0.8-0

enhance unit mapping for newly installed units; #290
remove deprecations: install_symbolic_unit, remove_symbolic_unit, install_conversion_constant, install_conversion_offset; #290
fix multipliers for round trip log-exp operations; #292
integrate ggplot2 scales (previously in the ggforce package) to automatically print axes with units; #294 addressing #164
fix all.equal.units for non-units current
fix zero power; #285
fix unique.units to support arrays and matrices, implement methods for duplicated and anyDuplicated
fix plot labels with spaces; #298 addressing #297
always add units to labels, including user-provided ones; as part of #298
new symbols/names with a percentage character are not allowed due to an upstream bug; #289

enhance pillar integration; #273, #275, #280 @krlmlr
new unique method for units and mixed_units objects; #283 addressing #277 @lewinfox

allow longer units grouping; #270 addressing #269 @bart1
fix regression in set_units method for mixed_units to ensure that ordering is preserved; #272 addressing #271

add load_units_xml to enable database reloading as well as loading user-provided unit systems; #254 addressing #243, #244
add install_unit and remove_unit for adding/removing custom user-defined symbols or names, with optional mapping to existing units; install_symbolic_unit, remove_symbolic_unit, install_conversion_constant, install_conversion_offset are deprecated; #261 addressing #89
add keep_units, a helper to apply functions that do not preserve units; #255 addressing #252
fix as_units(""), which is now equivalent to unitless; #199
fix plot axes for plot.formula and plot.data.frame; #213
fix arithmetic for powers above 1 and below -1; #264
improve arithmetic of logarithms; #249
export ud_are_convertible; #263 addressing #258 @cregouby
remove deprecations: as.units, as_cf, make_unit, parse_unit; #259
remove deprecated pre-computed ud_units database; #259

fix support for weights with units in weighted.mean; #205
invalid names for new units now trigger a proper error message; #209 addressing #208
fix issues in strict latin1 environments; #202

print units as [unit] more consistently, e.g. for single unit and in data.frames; #132
improve printing of unitless units; provide option to print something else than 1; #150
fix printing unitless in labels when negative_power is TRUE; #133
install_symbolic_unit now adds a dimensionless unit, integrated in the units system, meaning that prefixes on it work as well; #71
install_conversion_constant and install_conversion_offset now install a new unit that is a function of an existing udunits unit.; #71, #84
unit simplification can now be user-controlled by units_options; #89
set_units(15, mg/kg) is now no longer simplified to 1e-9 unitless; #89
directly uses the udunits2 C library; drop dependence on R package udunits2, fixing R package udunits2 memory leaks; #135
drops %*%, no longer gives warning when loading

deal with trigonometric functions for units degree; return units rad on inverse trigonometric functions.
Unit creation has been significantly refactored. units<- now accepts strings or quoted language objects on the right hand side, powered by new S3 methods for as_units. All valid unit symbols and unit names recognized by package 'udunits2' are now accepted. New user facing function make_units() (plural s) is also provided. See ?as_units for details. @t-kalinowski
new functions valid_udunits() and valid_udunits_prefixes() generate tidy dataframes listing all the valid unit names, symbols, and prefixes recognized by udunits. @t-kalinowski
new function install_symbolic_unit() for adding custom, user-defined units. @t-kalinowski
make_unit and parse_unit (singular unit) have been deprecated, please use as_units instead.
ud_units is no longer necessary and is soft-deprecated, and may be removed in a future release.
add %*% as an S3 generic; #54
add %% and %/% to Ops.units
support unary + and - ; #56
add seq method for units, converting units to those of the first argument
Deprecate as.dt for as_difftime, as.units for as_units and as_cf for deparse_unit

add all.equal method for units; #51
add deparse_unit to replace as_cf
add calender/time conversions between udunits time units like minutes from 1900-0-0, and R's POSIXct and Date
add as_units to replace as.units
rename as.dt to as_difftime

add support for user-defined unit conversion; #31
allow for 1/n integer powers, as in set_units(1:10, m^-2) ^ 0.5; #29
properly set log units after log transform; #33
sin, cos and tan no longer complain when units is rad, and return unitless; #40
now allow for set_units(1:3, "°C") and also set_units(1:3, "degree_Celsius") by resolving names to symbols first; #43
set_units(x) with x numeric sets units to unitless; #41

fix a result units bug when multiplying or dividing units vectors of different length, #34
add a rep method for units vectors

support for set_units(1:10, m) which does not require to declare or define, m (m is resolved automatically from ud_units)