select_which: Select columns satisfying a condition
In hutils: Miscellaneous R Functions and Aliases

select_which

R Documentation

Select columns satisfying a condition

Description

Select columns satisfying a condition

Usage

select_which(DT, Which, .and.dots = NULL, checkDT = TRUE, .and.grep = NULL)

Arguments

`DT`	A `data.table`.
`Which`	A function that takes a vector and returns `TRUE` or `FALSE`. `TRUE` columns are selected.
`.and.dots`	Optional extra columns to include. May be a character vector of `names(DT)` or numeric (positions) or logical. If provided, the columns so added (if they do not satisfy `Which`) will be after all the columns `Which` do so satisfy.
`checkDT`	If `TRUE` (the default), an informative error message is provided if `DT` is not a `data.table`.
`.and.grep`	A character vector of regular expressions to match to the names of `DT`. The corresponding columns will be included in the result.

Value

DT with the selected variables.

Examples

library(data.table)
DT <- data.table(x = 1:5,
                 y = letters[1:5],
                 AB = c(NA, TRUE, FALSE))
select_which(DT, anyNA, .and.dots = "y")

hutils documentation built on April 13, 2022, 5:23 p.m.