isReplicated: Identifies all entries with replicated values

In R.utils: Various Programming Utilities

Identifies all entries with replicated values

Description

Identifies all entries with replicated values, that is, with values that exist more than once.

Usage

 isReplicated(x, ...)
 replicates(x, ...)

Arguments

x	A vector of length K.
...	Additional arguments passed to duplicated().

Details

Let reps <- isReplicated(x). Then it always holds that:

• reps == rev(isReplicated(rev(x)))

• reps == duplicated(x) | duplicated(x, fromLast=TRUE)

• reps == !is.element(x, setdiff(x, unique(x[duplicated(x)])))

Value

A logical vector of length K, where TRUE indicates that the value exists elsewhere, otherwise not.

Author(s)

Henrik Bengtsson

See Also

Internally duplicated() is used. See also isSingle().

Examples

x <- c(1,1,2,3,4,2,1)
x <- base::letters[x]
print(x)

# Identify entries with replicated values
reps <- isReplicated(x)
print(x[reps])
stopifnot(x[reps] == replicates(x))

# Identify entries with unique values
print(x[!reps])
stopifnot(x[!reps] == singles(x))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Validation
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
x <- c(1,1,2,3,4,2,1)
x <- base::letters[x]
reps <- isReplicated(x)

stopifnot(all(table(x[reps]) > 1))
stopifnot(all(table(x[!reps]) == 1))
stopifnot(all(reps == rev(isReplicated(rev(x)))))
stopifnot(all(reps == duplicated(x) | duplicated(x, fromLast=TRUE)))
stopifnot(all(reps == !is.element(x, setdiff(x, unique(x[duplicated(x)])))))
stopifnot(all(sort(c(singles(x), replicates(x))) == sort(x)))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Benchmarking singles()
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
set.seed(0xBEEF)
n <- 1e6
x <- sample(1:(n/2), size=n, replace=TRUE)
t <- system.time({
  s <- isSingle(x)
})
print(sum(s))

t0 <- system.time({
  s0 <- !(x %in% x[duplicated(x)]);
})
print(t/t0)
stopifnot(all(s == s0))

R.utils documentation built on Nov. 18, 2023, 1:09 a.m.