biganalytics (version 1.1.12)

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

Description

These functions operate on columns of a big.matrix object.

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)
colna(x, cols)

Arguments

x

a big.matrix object.

cols

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

na.rm

if TRUE, remove NA values before summarizing.

...

options associated with the correspoding default Rfunction

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

bigmemory

Examples

x <- as.big.matrix(
  matrix( sample(1:10, 20, replace=TRUE), 5, 4, 
          dimnames=list( NULL, 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)