R: Select helpers

select_helpers {tidyselect}

R Documentation

Select helpers

Description

These functions allow you to select variables based on their names.

starts_with(): starts with a prefix
ends_with(): ends with a prefix
contains(): contains a literal string
matches(): matches a regular expression
num_range(): a numerical range like x01, x02, x03.
one_of(): variables in character vector.
everything(): all variables.
last_col(): last variable, possibly with an offset.

Usage

starts_with(match, ignore.case = TRUE, vars = peek_vars())

ends_with(match, ignore.case = TRUE, vars = peek_vars())

contains(match, ignore.case = TRUE, vars = peek_vars())

matches(match, ignore.case = TRUE, vars = peek_vars())

num_range(prefix, range, width = NULL, vars = peek_vars())

one_of(..., .vars = peek_vars())

everything(vars = peek_vars())

last_col(offset = 0L, vars = peek_vars())

Arguments

`match`	A string.
`ignore.case`	If `TRUE`, the default, ignores case when matching names.
`vars, .vars`	A character vector of variable names. When called from inside selecting functions like `dplyr::select()` these are automatically set to the names of the table.
`prefix`	A prefix that starts the numeric range.
`range`	A sequence of integers, like `1:5`
`width`	Optionally, the "width" of the numeric range. For example, a range of 2 gives "01", a range of three "001", etc.
`...`	One or more character vectors.
`offset`	Set it to `n` to select the nth var from the end.

Value

An integer vector giving the position of the matched variables.

Examples

nms <- names(iris)
vars_select(nms, starts_with("Petal"))
vars_select(nms, ends_with("Width"))
vars_select(nms, contains("etal"))
vars_select(nms, matches(".t."))
vars_select(nms, Petal.Length, Petal.Width)
vars_select(nms, everything())
vars_select(nms, last_col())
vars_select(nms, last_col(offset = 2))

vars <- c("Petal.Length", "Petal.Width")
vars_select(nms, one_of(vars))

[Package tidyselect version 0.2.4 Index]