Alternative S4 Constructor

An alternative version of new to create objects based on a list of values.

new2(class, ...)

Arguments

class	Class name to instanciate
...	extra arguments from which slot values are extracted by exact matching of names.

Examples

setClass('A', contain='character', representation(x='numeric', y='character'))

# identical behaviour with standard calls
identical(new('A'), new2('A'))
#> [1] TRUE
identical(new('A', x=1), new2('A', x=1))
#> [1] TRUE

# but if passing that are names not slots 
identical(new('A'), new2('A', b=1))
#> [1] TRUE
identical(new('A', x=1), new2('A', x=1, b=3))
#> [1] TRUE
identical(new('A', x=1), new2('A', x=1, b=3))
#> [1] TRUE

# standard `new` would coerce first unnamed argument into parent of 'A' (i.e. 'character') 
new('A', list(x=1))
#> An object of class "A"
#> [1] "1"
#> Slot "x":
#> numeric(0)
#> 
#> Slot "y":
#> character(0)
#> 
new('A', list(x=1, y='other'))
#> An object of class "A"
#> [1] "1"     "other"
#> Slot "x":
#> numeric(0)
#> 
#> Slot "y":
#> character(0)
#> 
# `new2` rather use it to initialise the slots it can find in the list 
identical(new('A', x=1), new2('A', list(x=1)))
#> [1] TRUE
identical(new('A', x=1, y='other'), new2('A', list(x=1, y='other')))
#> [1] TRUE