dataMaid (version 1.4.1)

isKey: Check if a variable qualifies as a key

Description

A checkFunction that checks if v is a key, that is, if every observation has a unique value in v and v is not a numeric/integer nor a Date variable. This function is intended for use as a precheck in makeDataReport.

Usage

isKey(v)

Value

A checkResult with three entires: $problem (a logical indicating whether v is a key), $message (if a problem was found, the following message: "The variable is a key (distinct values for each observation).", otherwise "") and $problemValues (always NULL).

Arguments

v

A variable (vector) to check. All variable types are allowed.

Details

Note that numeric or integer variables are not considered candidates for keys, as truly continuous measurements will most likely result in unique values for each observation.

See Also

check, allCheckFunctions, checkFunction, checkResult

Examples

keyVar <- c("a", "b", "c", "d", "e", "f")
notKeyVar <- c("a", "a", "b", "c", "d", "e", "f")

isKey(keyVar)
isKey(notKeyVar)