This function produces a ‘flat’ representation of a
high-dimensional contingency table constructed by recursive
splits (similar to the construction of mosaic displays).
Usage
## S3 method for class 'formula'
structable(formula, data,
direction = NULL, split_vertical = NULL, ..., subset, na.action)
## Default S3 method:
structable(..., direction = NULL, split_vertical = FALSE)
Arguments
formula
a formula object with possibly both left and right hand
sides specifying the column and row variables of the flat table.
data
a data frame, list or environment containing the variables
to be cross-tabulated, or an object inheriting from class table.
subset
an optional vector specifying a subset of observations
to be used.
Ignored if data is a contingency table.
na.action
a function which indicates what should happen when
the data contain NAs.
Ignored if data is a contingency table
...
R objects which can be interpreted as factors (including
character strings), or a list (or data frame) whose components can
be so interpreted, or a contingency table object of class
"table" or "ftable".
split_vertical
logical vector indicating, for each dimension,
whether it should be split vertically or not (default:
FALSE). Values are recycled as needed.
If the argument is of length 1, the value is alternated
for all dimensions. Ignored if direction is provided.
direction
character vector alternatively specifying the
splitting direction ("h" for horizontal and "v" for
vertical splits). Values are recycled as needed. If the argument
is of length 1, the value is alternated for all dimensions.
Details
This function produces textual representations of mosaic displays, and
thus ‘flat’ contingency tables. The formula interface is quite
similar to the one of ftable, but also accepts the
mosaic-like formula interface (empty left-hand
side). Note that even if the ftable interface is used,
the split_vertical or direction argument is needed to
specify the order of the horizontal and vertical splits.
If pretabulated data with a Freq column is used, than the
left-hand side should be left empty—the Freq column will be
handled correctly.
"structable" objects can be subset using the [ and [[
operators, using either level indices or names (see
examples). The corresponding replacement functions are available as well. In
addition, appropriate aperm, cbind,
rbind, length, dim, and
is.na methods do exist.
Value
An object of class "structable",
inheriting from class "ftable", with the splitting
information ("split_vertical") as additional attribute.
Meyer, D., Zeileis, A., and Hornik, K. (2006),
The strucplot framework: Visualizing multi-way contingency tables with
vcd.
Journal of Statistical Software, 17(3), 1-48.
URL http://www.jstatsoft.org/v17/i03/ and available as
vignette("strucplot").
See Also
strucplot,
mosaic,
ftable
Examples
structable(Titanic)
structable(Titanic, split_vertical = c(TRUE, TRUE, FALSE, FALSE))
structable(Titanic, direction = c("h","h","v","v"))
structable(Sex + Class ~ Survived + Age, data = Titanic)
## subsetting of structable objects
(hec <- structable(aperm(HairEyeColor)))
## The "[" operator treats structables as a block-matrix and selects parts of the matrix:
hec[1]
hec[2]
hec[1,c(2,4)]
hec["Male",c("Blue","Green")]
## replacement funcion:
tmp <- hec
(tmp[1,2:3] <- tmp[2,c(1,4)])
## In contrast, the "[[" operator treats structables as two-dimensional
## lists. Indexing conditions on specified levels and thus reduces the dimensionality:
## seek subtables conditioning on levels of the first dimension:
hec[[1]]
hec[[2]]
## Seek subtable from the first two dimensions, given the level "Male"
## of the first variable, and "Brown" from the second
## (the following two commands are equivalent):
hec[["Male"]][["Brown"]]
hec[[c("Male","Brown")]]
## Seeking subtables by conditioning on row and/or column variables:
hec[["Male","Hazel"]]
hec[[c("Male","Brown"),]]
hec[[c("Male","Brown"),"Hazel"]]
## a few other operations
t(hec)
dim(hec)
dimnames(hec)
as.matrix(hec)
length(hec)
cbind(hec[,1],hec[,3])
as.vector(hec) ## computed on the _multiway_ table
as.vector(unclass(hec))