mosaic (version 0.4-1)

as.xtabs: Convert objects to xtabs format

Description

Convert a data frame or a matrix into an xtabs object.

Usage

as.xtabs(x, ...)
  ## S3 method for class 'data.frame':
as.xtabs(x, rowvar = NULL,
    colvar = NULL, labels = 1, ...)
  ## S3 method for class 'matrix':
as.xtabs(x, rowvar = NULL,
    colvar = NULL, ...)

Arguments

x

object (typically a data frame) to be converted to xtabs format

...

additional arguments to be passed to or from methods.

rowvar

name of the row variable as character string

colvar

name of the column variable as character string

labels

column of data frame that contains the labels of the row variable.

Value

• An xtabs object.

Details

The intended use is to convert a two-way contingency table stored in a data frame or a matrix into an xtabs object.

Examples

# example from example(fisher.test)
df <- data.frame( X=c('Tea','Milk'), Tea=c(3,1), Milk=c(1,3) )
xt <- as.xtabs(df, rowvar="Guess", colvar="Truth"); xt
if (require(vcd)) { mosaic(xt) }