library("zoo")
make.par.list(letters[1:5], 1:5, 3, 5)$a
[1] 1
$b
[1] 2
$c
[1] 3
$d
[1] 4
$e
[1] 5
suppressWarnings( make.par.list(letters[1:5], 1:4, 3, 5, 99) )$a
[1] 1
$b
[1] 2
$c
[1] 3
$d
[1] 4
$e
[1] 1
make.par.list(letters[1:5], c(d=3), 3, 5, 99)$a
[1] 99
$b
[1] 99
$c
[1] 99
$d
[1] 3
$e
[1] 99
make.par.list(letters[1:5], list(d=1:2, 99), 3, 5)$a
[1] 99
$b
[1] 99
$c
[1] 99
$d
[1] 1 2 1
$e
[1] 99
make.par.list(letters[1:5], list(d=1:2, 99, 100), 3, 5)$a
[1] 99
$b
[1] 100
$c
[1] 99
$d
[1] 1 2 1
$e
[1] 100