sweep

R Base 3.6.2

Return an array obtained from an input array by sweeping out a summary statistic.

Syntax

sweep(x, MARGIN, STATS, FUN = "-", check.margin = TRUE, &#8230;)

Arguments

Parameter	Description
`x`	an array.
`MARGIN`	a vector of indices giving the extent(s) of x which correspond to STATS.
`STATS`	the summary statistic which is to be swept out.
`FUN`	the function to be used to carry out the sweep.
`check.margin`	logical. If TRUE (the default), warn if the length or dimensions of STATS do not match the specified dimensions of x. Set to FALSE for a small speed gain when you know that dimensions match.
`…`	optional arguments to FUN.

Return Value

An array with the same shape as x, but with the summary statistics swept out.

Details

FUN is found by a call to match.fun. As in the default, binary operators can be supplied if quoted or backquoted. FUN should be a function of two arguments: it will be called with arguments x and an array of the same dimensions generated from STATS by aperm. The consistency check among STATS, MARGIN and x is stricter if STATS is an array than if it is a vector. In the vector case, some kinds of recycling are allowed without a warning. Use sweep(x, MARGIN, as.array(STATS)) if STATS is a vector and you want to be warned if any recycling occurs.

Examples

Example

# NOT RUN {
require(stats) # for median
med.att <- apply(attitude, 2, median)
sweep(data.matrix(attitude), 2, med.att)  # subtract the column medians

## More sweeping:
A <- array(1:24, dim = 4:2)

## no warnings in normal use
sweep(A, 1, 5)
(A.min <- apply(A, 1, min))  # == 1:4
sweep(A, 1, A.min)
sweep(A, 1:2, apply(A, 1:2, median))

## warnings when mismatch
sweep(A, 1, 1:3)  # STATS does not recycle
sweep(A, 1, 6:1)  # STATS is longer

## exact recycling:
sweep(A, 1, 1:2)  # no warning
sweep(A, 1, as.array(1:2))  # warning
# }