tuple (version 0.4-02)

matchNone: Return a Symbol That Matches No Values

Description

The tag value is chosen from among special characters so that it does not appear anywhere in the reference input data. The shortest possible tag is chosen.

Usage

matchNone(x, table = list(c(".", "!", "/"), c("NA", "na")))

Arguments

x

A vector or matrix.

table

The lookup table against which to seek non-matches. This can be a simple vector, or it can be a list of two vectors.

Value

A string composed of the strings in the table. The default list choses the first non-matching value out of 179 values that are unlikely to be used in most real sets of data. If only table is specified, the possible values for a non-matching string, ordered from the most to the least preferable, are returned.

Details

This function is used in other packages by the same author to extend missing data handling in R. It provides for flexible missing data identifiers where needed by an S4 class, and similar unmatched identifiers for other dirty data problems.

Examples

my.x <- c(1,2,3,2,3,1,2)
matchNone(my.x)
matchNone(c(my.x,"."))
matchNone(c(my.x,".","!"))
matchNone(c(my.x,".","!","/"))
matchNone(c(my.x,".","!","/",".."))
matchNone(table = ".")