as_label: Create a default name for an R object

In hadley/rlang: Functions for Base Types and Core R and 'Tidyverse' Features

Create a default name for an R object

Description

as_label() transforms R objects into a short, human-readable description. You can use labels to:

• Display an object in a concise way, for example to labellise axes in a graphical plot.

• Give default names to columns in a data frame. In this case, labelling is the first step before name repair.

See also as_name() for transforming symbols back to a string. Unlike as_label(), as_name() is a well defined operation that guarantees the roundtrip symbol -> string -> symbol.

In general, if you don't know for sure what kind of object you're dealing with (a call, a symbol, an unquoted constant), use as_label() and make no assumption about the resulting string. If you know you have a symbol and need the name of the object it refers to, use as_name(). For instance, use as_label() with objects captured with enquo() and as_name() with symbols captured with ensym().

Usage

as_label(x)

Arguments

x	An object.

Transformation to string

• Quosures are squashed before being labelled.

• Symbols are transformed to string with as_string().

• Calls are abbreviated.

• Numbers are represented as such.

• Other constants are represented by their type, such as ⁠<dbl>⁠ or ⁠<data.frame>⁠.

See Also

as_name() for transforming symbols back to a string deterministically.

Examples

# as_label() is useful with quoted expressions:
as_label(expr(foo(bar)))

as_label(expr(foobar))

# It works with any R object. This is also useful for quoted
# arguments because the user might unquote constant objects:
as_label(1:3)

as_label(base::list)

hadley/rlang documentation built on April 24, 2024, 1:05 a.m.