bigmemory (version 3.6)

colmean, colmin, colmax, colrange, colvar, colsd, colprod, colsum: Basic statistics for ``big.matrix'' objects.

Description

These functions operate on columns of the big.matrix.

Usage

colmean(x, cols, na.rm)
colmin(x, cols, na.rm)
colmax(x, cols, na.rm)
colrange(x, cols, na.rm)
colvar(x, cols, na.rm)
colsd(x, cols, na.rm)
colsum(x, cols, na.rm)
colprod(x, cols, na.rm)

Arguments

x

a big.matrix.

cols

a scalar or vector of column(s) to be summarized.

na.rm

if TRUE, remove NA values before summarizing.

Value

• For colrange, a matrix with two columns and length(cols) rows; column 1 contains the minimum, and column 2 contains the maximum for that column. The other functions return vectors of length length(cols).

Details

These functions essentially apply summary functions to each column (or each specified column) of the big.matrix in turn.

See Also

big.matrix

Examples

x <- as.big.matrix(matrix(sample(1:10, 20, replace=TRUE), 5, 4))
colnames(x) <- c("a", "b", "c", "d")
x[,]
mean(x)
colmean(x)
colmin(x)
colmin(x, 1)
colmax(x)
colmax(x, "b")
colsd(x)
colrange(x)
range(x)
colsum(x)
colprod(x)