uniquemap.default: Map Duplicate Entries to Unique Entries

Description

Determine whether entries in a vector (or rows in a matrix or data frame) are duplicated, choose a unique representative for each set of duplicates, and map the duplicates to the unique representative.

Usage

# S3 method for default
uniquemap(x)
# S3 method for data.frame
uniquemap(x)
# S3 method for matrix
uniquemap(x)

Arguments

A vector, data frame or matrix, or another type of data.

Value

An integer vector.

Details

The function uniquemap is generic, with methods for point patterns, data frames, and a default method.

The default method expects a vector. It determines whether any entries of the vector x are duplicated, and constructs a mapping of the indices of x so that all duplicates are mapped to a unique representative index.

The result is an integer vector u such that u[j] = i if the entries x[i] and x[j] are identical and point i has been chosen as the unique representative. The entry u[i] = i means either that point i is unique, or that it has been chosen as the unique representative of its equivalence class.

The method for data.frame determines whether any rows of the data frame x are duplicated, and constructs a mapping of the row indices so that all duplicate rows are mapped to a unique representative row.

Examples

Run this code

# NOT RUN {
  x <- c(3, 5, 2, 4, 2, 3)
  uniquemap(x)

  df <- data.frame(A=x, B=42)
  uniquemap(df)

  z <- cbind(x, 10-x)
  uniquemap(z)
# }