makeIntersectList {plotrix}R Documentation

Count set intersections

Description

Create a list of set intersections from a matrix of indicators.

Usage

 makeIntersectList(x,xnames=NULL)

Arguments

x A data frame or matrix where rows represent objects and columns attributes. A 1 or TRUE indicates that the object (row) has that attribute or is a member of that set (column).
xnames Optional user-supplied names for the categories of x.

Details

makeIntersectList reads a matrix (or data frame) containing only dichotomous values (either 0/1 or FALSE/TRUE). Each row represents an object and each column represents a set. A value of 1 or TRUE indicates that that object is a member of that set. The function creates a list of vectors that correspond to all combinations of the sets (set intersections) and inserts the counts of elements in each combination. If a row of the matrix is all zeros, it will not be counted, but the last element of the list returned contains the count of rows in x and thus non-members can be calculated.

makeIntersectList combines the set or attribute names to form intersection names. For the intersection of sets A and B, the name will be AB and so on. These are the names that will be displayed by intersectDiagram. To change these, use the xnames argument.

Value

A list of the intersection counts or percentages and the total number of objects.

Author(s)

Jim Lemon

See Also

intersectDiagram, pasteCols

Examples

 # create a matrix where each row represents an element and
 # a 1 (or TRUE) in each column indicates that the element is a member
 # of that set.
 setdf<-data.frame(A=sample(c(0,1),100,TRUE,prob=c(0.7,0.3)),
  B=sample(c(0,1),100,TRUE,prob=c(0.7,0.3)),
  C=sample(c(0,1),100,TRUE,prob=c(0.7,0.3)),
  D=sample(c(0,1),100,TRUE,prob=c(0.7,0.3)))
 setdflist<-makeIntersectList(setdf)
 setdflist

[Package plotrix version 2.5-5 Index]