gdata (version 2.18.0)

duplicated2: Determine Duplicate Elements

Description

duplicated2() determines which elements of a vector or data frame are duplicates, and returns a logical vector indicating which elements (rows) are duplicates.

Usage

duplicated2(x, bothWays=TRUE, ...)

Arguments

x

a vector or a data frame or an array or NULL.

bothWays

if TRUE (the default), duplication should be considered from both sides. For more information see the argument fromLast to the function duplicated.

…

further arguments passed down to duplicated() and its methods.

Value

For a vector input, a logical vector of the same length as x. For a data frame, a logical vector with one element for each row. For a matrix or array, and when MARGIN = 0, a logical array with the same dimensions and dimnames.

For more details see duplicated.

Details

The standard duplicated function (in package:base) only returns TRUE for the second and following copies of each duplicated value (second-to-last and earlier when fromLast=TRUE). This function returns all duplicated elementes, including the first (last) value.

When bothWays is FALSE, duplicated2() defaults to a duplicated call. When bothWays is TRUE, the following call is being executed: duplicated(x, ...) | duplicated(x, fromLast=TRUE, ...)

See Also

duplicated, unique

Examples

# NOT RUN {
  data(iris)
  iris[duplicated(iris), ]                 # 2nd duplicated value
  iris[duplicated(iris, fromLast=TRUE), ]  # 1st duplicated value
  iris[duplicated2(iris), ]                # both duplicated values
# }