plotrix (version 3.7-4)

makeIntersectList: Count set intersections

Description

Create a list of set intersections from a matrix of indicators

Usage

makeIntersectList(x,xnames=NULL,sep="+")

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). x can also be a matrix or data frame in which the first column contains object identifiers and the second contains attribute codes.

xnames

Optional user-supplied names for the attributes of x.

sep

A character to use as a separator for attribute labels.

Value

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

Details

makeIntersectList reads a matrix (or data frame where all values are the same type) containing dichotomous values (either 0/1 or FALSE/TRUE) or labels (see next paragraph). In the first type of input, 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 x is all zeros, it will not be counted, but the second last element of the list returned contains the count of rows in x and thus non-members can be calculated.

If a matrix (or data frame where all values are the same type) containing values other than 0/1 or TRUE/FALSE, it will be passed to categoryReshape for conversion to a data frame as described above. See categoryReshape for details of this.

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

See Also

intersectDiagram, pasteCols, linkcategoryReshape

Examples

Run this code
# NOT RUN {
 # 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)))
 makeIntersectList(setdf)
 ns<-sample(1:8,20,TRUE)
 objects<-0
 for(i in 1:length(ns)) objects<-c(objects,rep(i,ns[i]))
 attributes<-"Z"
 for(i in 1:length(ns)) attributes<-c(attributes,sample(LETTERS[1:8],ns[i]))
 setdf2<-data.frame(objects[-1],attributes[-1])
 makeIntersectList(setdf2)
# }

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