sweep(x, MARGIN, STATS, FUN = "-", check.margin = TRUE, ...)x
which correspond to STATS.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.FUN.x, but with the summary
statistics swept out.
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.
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
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