| merge.table {mining} | R Documentation |
Merges similar rows and columns of a contingency table.
merge.table(x, bins=rep(2,length(ds)), ds=1:length(dim(x)))
x |
a table |
bins |
the desired number of levels for each dimension being merged.
a numeric vector, the same length as ds. |
ds |
a vector of dimensions to merge, either by name or number. default is all of them. |
The desired table dimensions are achieved by successively merging the
two most similar slices.
(`Slice' generalizes `row' and `column' to higher-dimensional tables.)
The distance between slices
is measured according to the chi-square statistic.
Merging two slices means adding together their counts, and
concatenating their labels with a comma in between.
If a dimension is ordered (according to dim.ordered), only
adjacent slices are considered for merging, and their labels are concatenated
with a dash in between.
A merged table. The total count is the same as x.
A merging trace is plotted which shows, for each merge, the chi-square
distance of the slices which were merged.
This is useful for determining
the appropriate dimensions. An interesting number is one
that directly precedes a sudden jump in the chi-square distance.
Tom Minka
sort.table,
mosaicplot,
linechart
i <- factor(c(1,1,2,2,3,3,4,4)) j <- factor(c(3,4,3,4,1,2,1,2)) x <- table(i,j) merge.table(x,c(2,2)) i <- factor(c(1,1,3,3,2,2,4,4)) j <- factor(c(2,4,2,4,1,3,1,3)) x <- table(i,j) merge.table(x,c(2,2)) # one ordered dimension data(education) merge.table(education,c(3,2)) data(occupation) merge.table(occupation,c(3,4))