# S3 method for formula
ftable(formula, data = NULL, subset, na.action, …)
model.frame
) containing the variables
to be cross-tabulated, or a contingency table (see below).data
is a contingency table.NA
s.
Ignored if data
is a contingency table.ftable.default
.ftable
. The left and right hand side of formula
specify the column and
row variables, respectively, of the flat contingency table to be
created. Only the +
operator is allowed for combining the
variables. A .
may be used once in the formula to indicate
inclusion of all the remaining variables. If data
is an object of class "table"
or an array with
more than 2 dimensions, it is taken as a contingency table, and hence
all entries should be nonnegative. Otherwise, if it is not a flat
contingency table (i.e., an object of class "ftable"
), it
should be a data frame or matrix, list or environment containing the
variables to be cross-tabulated. In this case, na.action
is
applied to the data to handle missing values, and, after possibly
selecting a subset of the data as specified by the subset
argument, a contingency table is computed from the variables. The contingency table is then collapsed to a flat table, according to
the row and column variables specified by formula
.ftable
,
ftable.default
;
table
.Titanic
x <- ftable(Survived ~ ., data = Titanic)
x
ftable(Sex ~ Class + Age, data = x)
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