select_helpers

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Select helpers

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.

Aliases
  • select_helpers
  • starts_with
  • ends_with
  • contains
  • matches
  • num_range
  • one_of
  • everything
  • last_col
Examples
library(tidyselect) # NOT RUN { 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)) # }
Documentation reproduced from package tidyselect, version 0.2.4, License: GPL-3

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