R: Install a conversion constant or offset between user-defined...

install_conversion_constant {units} | R Documentation

## Install a conversion constant or offset between user-defined units.

### Description

Tells the `units` package how to convert between units that have a linear relationship, i.e. can be related on the form y = α x (constant) or y = α + x (offset).

### Usage

    install_conversion_constant(from, to, const)

    install_conversion_offset(from, to, const)

### Arguments

`from` | String for the symbol of the unit being converted from.
`to` | String for the symbol of the unit being converted to. One of `from` and `to` must be an existing unit name.
`const` | The constant α in the conversion.

### Details

This function handles the very common case where units are related through a linear function, that is, you can convert from one to the other as y = α x. Using this function, you specify that you can go from values of type `from` to values of type `to` by multiplying by a constant, or adding a constant.

### See Also

`install_symbolic_unit`, `remove_symbolic_unit`

### Examples

    # one orange is worth two apples
    install_symbolic_unit("orange")
    install_conversion_constant("orange", "apple", 2) # apple = 2 * orange
    apples <- 2 * as_units("apple")
    oranges <- 1 * as_units("orange")
    apples + oranges
    oranges + apples

    install_conversion_offset("meter", "newmeter", 1)
    m = set_units(1:3, meter)
    n = set_units(1:3, newmeter)
    m + n
    n + m

[Package units version 0.6-7 Index]