# NOT RUN {
x <- data.frame(a = runif(1000), b = runif(1000))
x <- round(x, digits=2)
isSorted(x, c("a", "b"))
x <- x[order(x$a, x$b),]
isSorted(x, c("a", "b"))
x <- x[order(x$a,-x$b),]
isSorted(x, c("a", "b"), c(TRUE, FALSE))
# }
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