nc (version 2025.3.24)

measure: measure

Description

Computes a value to be used as measure.vars argument to melt.data.table. NOTE: only works on newer versions of data.table that include the measure function.

Usage

measure(..., cols)

Value

List or vector to use as measure.vars argument to melt.data.table.

Arguments

...

Regular expression pattern list, passed to capture_first_vec with cols as subject.

cols

Character vector, column names to match with regex.

Author

Toby Hocking <[e-mail]> [aut, cre]

Details

measure_multiple is called if there is a capture group named "column" and measure_single is called otherwise.

Examples

library(data.table)
iris.dt <- data.table(datasets::iris[c(1,150),])
melt(iris.dt, measure=nc::measure(part  =".*", "[.]", dim   =".*"))
melt(iris.dt, measure=nc::measure(column=".*", "[.]", dim   =".*"))
melt(iris.dt, measure=nc::measure(part  =".*", "[.]", column=".*"))