as_string: Cast symbol to string

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

Cast symbol to string

Description

as_string() converts symbols to character strings.

Usage

as_string(x)

Arguments

x	A string or symbol. If a string, the attributes are removed, if any.

Value

A character vector of length 1.

Unicode tags

Unlike base::as.symbol() and base::as.name(), as_string() automatically transforms unicode tags such as "<U+5E78>" to the proper UTF-8 character. This is important on Windows because:

• R on Windows has no UTF-8 support, and uses native encoding instead.

• The native encodings do not cover all Unicode characters. For example, Western encodings do not support CKJ characters.

• When a lossy UTF-8 -> native transformation occurs, uncovered characters are transformed to an ASCII unicode tag like "<U+5E78>".

• Symbols are always encoded in native. This means that transforming the column names of a data frame to symbols might be a lossy operation.

• This operation is very common in the tidyverse because of data masking APIs like dplyr where data frames are transformed to environments. While the names of a data frame are stored as a character vector, the bindings of environments are stored as symbols.

Because it reencodes the ASCII unicode tags to their UTF-8 representation, the string -> symbol -> string roundtrip is more stable with as_string().

See Also

as_name() for a higher-level variant of as_string() that automatically unwraps quosures.

Examples

# Let's create some symbols:
foo <- quote(foo)
bar <- sym("bar")

# as_string() converts symbols to strings:
foo
as_string(foo)

typeof(bar)
typeof(as_string(bar))

hadley/rlang documentation built on Dec. 17, 2024, 3:26 a.m.