select_vars: Select variables.

In sctyner/dplyr050: A Grammar of Data Manipulation

Description

These functions power select() and rename().

Usage

select_vars(vars, ..., include = character(), exclude = character())

select_vars_(vars, args, include = character(), exclude = character())

rename_vars(vars, ...)

rename_vars_(vars, args)

Arguments

vars	A character vector of existing column names.
..., args	Expressions to compute. select_vars and rename_vars
include, exclude	Character vector of column names to always include/exclude.

Value

A named character vector. Values are existing column names, names are new names.

Examples

# Keep variables
select_vars(names(iris), everything())
select_vars(names(iris), starts_with("Petal"))
select_vars(names(iris), ends_with("Width"))
select_vars(names(iris), contains("etal"))
select_vars(names(iris), matches(".t."))
select_vars(names(iris), Petal.Length, Petal.Width)
select_vars(names(iris), one_of("Petal.Length", "Petal.Width"))

df <- as.data.frame(matrix(runif(100), nrow = 10))
df <- df[c(3, 4, 7, 1, 9, 8, 5, 2, 6, 10)]
select_vars(names(df), num_range("V", 4:6))

# Drop variables
select_vars(names(iris), -starts_with("Petal"))
select_vars(names(iris), -ends_with("Width"))
select_vars(names(iris), -contains("etal"))
select_vars(names(iris), -matches(".t."))
select_vars(names(iris), -Petal.Length, -Petal.Width)

# Rename variables
select_vars(names(iris), petal_length = Petal.Length)
select_vars(names(iris), petal = starts_with("Petal"))

# Rename variables preserving all existing
rename_vars(names(iris), petal_length = Petal.Length)

# Standard evaluation -------------------------------------------------------
# You can use names, calls, formulas (or lists of), or a character vector
select_vars_(names(iris), list(~Petal.Length))
select_vars_(names(iris), list(quote(Petal.Length)))
select_vars_(names(iris), "Petal.Length")

sctyner/dplyr050 documentation built on May 17, 2019, 2:22 p.m.