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_string() 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_string(). For instance, use as_label() with
objects captured with enquo() and as_string() with symbols
captured with ensym().
as_label(x)
| x | An object. |
|---|
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>.
Note that simple symbols should generally be transformed to strings
with as_name(). Labelling is not a well defined operation and
no assumption should be made about how the label is created. On the
other hand, as_name() only works with symbols and is a well
defined, deterministic operation.
as_name() for transforming symbols back to a string
deterministically.
# 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>"