Return an array obtained from an input array by sweeping out a summary statistic.
sweep(x, MARGIN, STATS, FUN = "-", check.margin = TRUE, ...)
an array, including a matrix.
a vector of indices giving the extent(s) of
the summary statistic which is to be swept out.
the function to be used to carry out the sweep.
optional arguments to
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
x and an array of the same dimensions generated
The consistency check among
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
sweep(x, MARGIN, as.array(STATS)) if
is a vector and you want to be warned if any recycling occurs.
An array with the same shape as
x, but with the summary
statistics swept out.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
apply on which
sweep used to be based;
scale for centering and scaling.
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 ## Using named dimnames dimnames(A) <- list(fee=1:4, fie=1:3, fum=1:2) mn_fum_fie <- apply(A, c("fum", "fie"), mean) mn_fum_fie sweep(A, c("fum", "fie"), mn_fum_fie)
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