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().
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)))
#> [1] "foo(bar)"
as_label(expr(foobar))
#> [1] "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)
#> [1] "<int>"
as_label(base::list)
#> [1] "<fn>"