get_interpolated_expr: Lists the expressions used for interpolation in a...

In stringmagic: Character String Operations and Interpolation, Magic Edition

Lists the expressions used for interpolation in a string_magic call

Description

Tool intended for development: use get_interpolated_expr to obtain the list of expressions which will be interpolated in a string_magic() call. The function get_interpolated_vars provides the variables instead.

Usage

get_interpolated_expr(x, parse = FALSE, delim = c("{", "}"))

get_interpolated_vars(x, delim = c("{", "}"))

Arguments

x	A character scalar for which the variables will be recovered. For example x = "Hi {person}" will return "person" (the variable that will be interpolated).
parse	Logical scalar, default is FALSE. If TRUE, the result is a list of R expressions. If FALSE (default), the result is a character vector of expressions.
delim	Character vector of length 1 or 2. Default is c("{", "}"). Defines the opening and the closing delimiters for interpolation. If of length 1, it must be of the form: 1) the opening delimiter, 2) a single space, 3) the closing delimiter. Ex: ".[ ]" is equivalent to c(".[", "]"). The default value is equivalent to "{ }". [ ]: R:%20 [", "]: R:%22,%20%22

Details

Note that this function captures even deeply nested interpolations.

Value

If the argument parse = FALSE, the default, then this function returns a character vector containing all the expressions that will be interpolated. This vector can be empty if there is no interpolation.

If the argument parse = TRUE, then a list is returned, containing the R expressions.

The function get_interpolated_vars always return a character vector.

Functions

• get_interpolated_vars(): Obtain the variables used in string_magic() interpolations

See Also

String operations: string_is(), string_get(), string_clean(), string_split2df(). Chain basic operations with string_ops(). Clean character vectors efficiently with string_clean().

Use string_vec() to create simple string vectors.

String interpolation combined with operation chaining: string_magic(). You can change string_magic default values with string_magic_alias() and add custom operations with string_magic_register_fun().

Display messages while benefiting from string_magic interpolation with cat_magic() and message_magic().

Other tools with aliases: cat_magic_alias(), string_magic(), string_magic_alias(), string_ops_alias(), string_vec_alias()

Examples

# let's create a simple interpolation
x = c("Ken", "Barbie")
sma_expr = "{' loves 'c ? x}. But does {' love 'c ? rev(x)}?"
string_magic(sma_expr)

# We recover the two expressions
(char = get_interpolated_expr(sma_expr))

# same with parsing
(expr = get_interpolated_expr(sma_expr, parse = TRUE))

# see the difference
eval(char[[1]])
eval(expr[[1]])

# and only the variables:
get_interpolated_vars(sma_expr)

stringmagic documentation built on June 8, 2025, 12:41 p.m.