| Line 1... |
Line 1... |
| 1 |
% File src/library/stats/man/model.matrix.Rd
|
1 |
% File src/library/stats/man/model.matrix.Rd
|
| 2 |
% Part of the R package, https://www.R-project.org
|
2 |
% Part of the R package, https://www.R-project.org
|
| 3 |
% Copyright 1995-2016 R Core Team
|
3 |
% Copyright 1995-2019 R Core Team
|
| 4 |
% Distributed under GPL 2 or later
|
4 |
% Distributed under GPL 2 or later
|
| 5 |
|
5 |
|
| 6 |
\name{model.matrix}
|
6 |
\name{model.matrix}
|
| 7 |
\alias{model.matrix}
|
7 |
\alias{model.matrix}
|
| 8 |
\alias{model.matrix.default}
|
8 |
\alias{model.matrix.default}
|
| Line 17... |
Line 17... |
| 17 |
\arguments{
|
17 |
\arguments{
|
| 18 |
\item{object}{an object of an appropriate class. For the default
|
18 |
\item{object}{an object of an appropriate class. For the default
|
| 19 |
method, a model \link{formula} or a \code{\link{terms}} object.}
|
19 |
method, a model \link{formula} or a \code{\link{terms}} object.}
|
| 20 |
\item{data}{a data frame created with \code{\link{model.frame}}. If
|
20 |
\item{data}{a data frame created with \code{\link{model.frame}}. If
|
| 21 |
another sort of object, \code{model.frame} is called first.}
|
21 |
another sort of object, \code{model.frame} is called first.}
|
| 22 |
\item{contrasts.arg}{A list, whose entries are values (numeric
|
22 |
\item{contrasts.arg}{a list, whose entries are values (numeric
|
| 23 |
matrices or character strings naming functions) to be used
|
23 |
matrices, \code{\link{function}}s or character strings naming
|
| - |
|
24 |
functions) to be used
|
| 24 |
as replacement values for the \code{\link{contrasts}}
|
25 |
as replacement values for the \code{\link{contrasts}}
|
| 25 |
replacement function and whose names are the names of
|
26 |
replacement function and whose names are the names of
|
| 26 |
columns of \code{data} containing \code{\link{factor}}s.}
|
27 |
columns of \code{data} containing \code{\link{factor}}s.}
|
| 27 |
\item{xlev}{to be used as argument of \code{\link{model.frame}} if
|
28 |
\item{xlev}{to be used as argument of \code{\link{model.frame}} if
|
| 28 |
\code{data} is such that \code{model.frame} is called.}
|
29 |
\code{data} is such that \code{model.frame} is called.}
|
| Line 45... |
Line 46... |
| 45 |
formula must be logical, integer, numeric or factor.
|
46 |
formula must be logical, integer, numeric or factor.
|
| 46 |
|
47 |
|
| 47 |
If \code{contrasts.arg} is specified for a factor it overrides the
|
48 |
If \code{contrasts.arg} is specified for a factor it overrides the
|
| 48 |
default factor coding for that variable and any \code{"contrasts"}
|
49 |
default factor coding for that variable and any \code{"contrasts"}
|
| 49 |
attribute set by \code{\link{C}} or \code{\link{contrasts}}.
|
50 |
attribute set by \code{\link{C}} or \code{\link{contrasts}}.
|
| - |
|
51 |
Whereas invalid \code{contrasts.arg}s have been ignored always, they are
|
| - |
|
52 |
warned about since \R version 3.6.0.
|
| 50 |
|
53 |
|
| 51 |
In an interaction term, the variable whose levels vary fastest is the
|
54 |
In an interaction term, the variable whose levels vary fastest is the
|
| 52 |
first one to appear in the formula (and not in the term), so in
|
55 |
first one to appear in the formula (and not in the term), so in
|
| 53 |
\code{~ a + b + b:a} the interaction will have \code{a} varying
|
56 |
\code{~ a + b + b:a} the interaction will have \code{a} varying
|
| 54 |
fastest.
|
57 |
fastest.
|
| Line 92... |
Line 95... |
| 92 |
ff <- log(Volume) ~ log(Height) + log(Girth)
|
95 |
ff <- log(Volume) ~ log(Height) + log(Girth)
|
| 93 |
utils::str(m <- model.frame(ff, trees))
|
96 |
utils::str(m <- model.frame(ff, trees))
|
| 94 |
mat <- model.matrix(ff, m)
|
97 |
mat <- model.matrix(ff, m)
|
| 95 |
|
98 |
|
| 96 |
dd <- data.frame(a = gl(3,4), b = gl(4,1,12)) # balanced 2-way
|
99 |
dd <- data.frame(a = gl(3,4), b = gl(4,1,12)) # balanced 2-way
|
| 97 |
options("contrasts")
|
100 |
options("contrasts") # typically 'treatment' (for unordered factors)
|
| 98 |
model.matrix(~ a + b, dd)
|
101 |
model.matrix(~ a + b, dd)
|
| 99 |
model.matrix(~ a + b, dd, contrasts = list(a = "contr.sum"))
|
102 |
model.matrix(~ a + b, dd, contrasts = list(a = "contr.sum"))
|
| 100 |
model.matrix(~ a + b, dd, contrasts = list(a = "contr.sum", b = "contr.poly"))
|
103 |
model.matrix(~ a + b, dd, contrasts = list(a = "contr.sum", b = contr.poly))
|
| 101 |
m.orth <- model.matrix(~a+b, dd, contrasts = list(a = "contr.helmert"))
|
104 |
m.orth <- model.matrix(~a+b, dd, contrasts = list(a = "contr.helmert"))
|
| 102 |
crossprod(m.orth) # m.orth is ALMOST orthogonal
|
105 |
crossprod(m.orth) # m.orth is ALMOST orthogonal
|
| - |
|
106 |
# invalid contrasts.. ignored with a warning:
|
| - |
|
107 |
stopifnot(identical(
|
| - |
|
108 |
model.matrix(~ a + b, dd),
|
| - |
|
109 |
model.matrix(~ a + b, dd, contrasts.arg = "contr.FOO")))
|
| 103 |
}
|
110 |
}
|
| 104 |
\keyword{models}
|
111 |
\keyword{models}
|
The R Project SVN
R