gdata: duplicated2 – R documentation

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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.

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, ...)

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.

Author(s)

Liviu Andronic

Examples

data(iris)
  iris[duplicated(iris), ]                 # 2nd duplicated value
  iris[duplicated(iris, fromLast=TRUE), ]  # 1st duplicated value
  iris[duplicated2(iris), ]                # both duplicated values

gdata

Various R Programming Tools for Data Manipulation

v2.18.0

GPL-2

Authors

Gregory R. Warnes, Ben Bolker, Gregor Gorjanc, Gabor Grothendieck, Ales Korosec, Thomas Lumley, Don MacQueen, Arni Magnusson, Jim Rogers, and others

Initial release

2017-06-05