Matrix Manipulation Tools

Description

Converts a matrix to a list, calculates matrix fill, or exclude rows/columns with certain rox/column sums.

Usage

mat2list(x, MARGIN = 1)
mfill(x)
rdrop(x, cutoff = 0, attrib = FALSE)
cdrop(x, cutoff = 0, attrib = FALSE)

Arguments

Value

mat2list returns a list of length nrow(x) or ncol(x) depending on MARGIN. Elements are rows/columns of x. Dimnames are retained as names.

mfill returns a single number with the matrix fill value.

rdrop and cdrop returns the original object but excluding rows (rdrop), or columns (cdrop) that has sum <= cutoff. Excluded row/colum numbers and specifications are stored in the "exclude" attribute of attrib = TRUE.

Author(s)

P'eter S'olymos, solymos@ualberta.ca

References

S'olymos P. (2008) mefa: an R package for handling and reporting count data. Community Ecology 9, 125–127.

S'olymos P. (2009) Processing ecological data in R with the mefa package. Journal of Statistical Software 29(8), 1–28. http://www.jstatsoft.org/v29/i08/

http://mefa.r-forge.r-project.org/

Examples

x <- matrix(1:12, 3, 4)
rownames(x) <- letters[1:3]
colnames(x) <- LETTERS[1:4]
mat2list(x, 1)
mat2list(x, 2)
x[2, ] <- 0
x[, 2] <- 0
mfill(x)
mfill(x) == sum(x > 0) / prod(dim(x))
rdrop(x)
cdrop(x)
cdrop(x, cutoff = 5)
cdrop(x, cutoff = 22) # be careful

Results