Drop empty variables

Convert an mvp object which is a pure constant into a scalar whose value is the coefficient of the empty term.

A few functions in the package (currently subs(), subsy()) take a drop argument that behaves much like the drop argument in base extraction.

Function drop() is an S4 generic, which is why the package calls setOldClass().

Function drop() was formerly called lose().

Usage

# S4 method for class 'mvp'
drop(x)

Arguments

x

Object of class mvp

Author

Robin K. S. Hankin

See also

subs

Examples

(m1 <- as.mvp("1+bish +bash^2 + bosh^3"))
#> mvp object algebraically equal to
#> 1 + bash^2 + bish + bosh^3
(m2 <- as.mvp("bish +bash^2 + bosh^3"))
#> mvp object algebraically equal to
#> bash^2 + bish + bosh^3

m1-m2         # an mvp object
#> mvp object algebraically equal to
#> 1
drop(m1-m2)   # numeric
#> [1] 1