glue: Format and interpolate a string
In glue: Interpreted String Literals

View source: R/glue.R

glue	R Documentation

Format and interpolate a string

Description

Expressions enclosed by braces will be evaluated as R code. Long strings are broken by line and concatenated together. Leading whitespace and blank lines from the first and last lines are automatically trimmed.

Usage

glue_data(
  .x,
  ...,
  .sep = "",
  .envir = parent.frame(),
  .open = "{",
  .close = "}",
  .na = "NA",
  .null = character(),
  .comment = "#",
  .literal = FALSE,
  .transformer = identity_transformer,
  .trim = TRUE
)

glue(
  ...,
  .sep = "",
  .envir = parent.frame(),
  .open = "{",
  .close = "}",
  .na = "NA",
  .null = character(),
  .comment = "#",
  .literal = FALSE,
  .transformer = identity_transformer,
  .trim = TRUE
)

Arguments

`.x`	[`listish`] An environment, list, or data frame used to lookup values.
`...`	[`expressions`] Unnamed arguments are taken to be expression string(s) to format. Multiple inputs are concatenated together before formatting. Named arguments are taken to be temporary variables available for substitution.
`.sep`	[`character(1)`: ‘""’] Separator used to separate elements.
`.envir`	[`environment`: `parent.frame()`] Environment to evaluate each expression in. Expressions are evaluated from left to right. If `.x` is an environment, the expressions are evaluated in that environment and `.envir` is ignored. If `NULL` is passed, it is equivalent to `emptyenv()`.
`.open`	[`character(1)`: ‘\{’] The opening delimiter. Doubling the full delimiter escapes it.
`.close`	[`character(1)`: ‘\}’] The closing delimiter. Doubling the full delimiter escapes it.
`.na`	[`character(1)`: ‘NA’] Value to replace `NA` values with. If `NULL` missing values are propagated, that is an `NA` result will cause `NA` output. Otherwise the value is replaced by the value of `.na`.
`.null`	[`character(1)`: ‘character()’] Value to replace NULL values with. If `character()` whole output is `character()`. If `NULL` all NULL values are dropped (as in `paste0()`). Otherwise the value is replaced by the value of `.null`.
`.comment`	[`character(1)`: ‘#’] Value to use as the comment character.
`.literal`	[`boolean(1)`: ‘FALSE’] Whether to treat single or double quotes, backticks, and comments as regular characters (vs. as syntactic elements), when parsing the expression string. Setting `.literal = TRUE` probably only makes sense in combination with a custom `.transformer`, as is the case with `glue_col()`. Regard this argument (especially, its name) as experimental.
`.transformer`	[`function]` A function taking three parameters `code`, `envir` and `data` used to transform the output of each block before, during, or after evaluation. For example transformers see `vignette("transformers")`.
`.trim`	[`logical(1)`: ‘TRUE’] Whether to trim the input template with `trim()` or not.

Examples

name <- "Fred"
age <- 50
anniversary <- as.Date("1991-10-12")
glue('My name is {name},',
  'my age next year is {age + 1},',
  'my anniversary is {format(anniversary, "%A, %B %d, %Y")}.')

# single braces can be inserted by doubling them
glue("My name is {name}, not {{name}}.")

# Named arguments can be used to assign temporary variables.
glue('My name is {name},',
  ' my age next year is {age + 1},',
  ' my anniversary is {format(anniversary, "%A, %B %d, %Y")}.',
  name = "Joe",
  age = 40,
  anniversary = as.Date("2001-10-12"))

# `glue()` can also be used in user defined functions
intro <- function(name, profession, country){
  glue("My name is {name}, a {profession}, from {country}")
}
intro("Shelmith", "Senior Data Analyst", "Kenya")
intro("Cate", "Data Scientist", "Kenya")

# `glue_data()` is useful in magrittr pipes
if (require(magrittr)) {

mtcars %>% glue_data("{rownames(.)} has {hp} hp")

# Or within dplyr pipelines
if (require(dplyr)) {

head(iris) %>%
  mutate(description = glue("This {Species} has a petal length of {Petal.Length}"))

}}

# Alternative delimiters can also be used if needed
one <- "1"
glue("The value of $e^{2\\pi i}$ is $<<one>>$.", .open = "<<", .close = ">>")

glue documentation built on March 18, 2022, 7:21 p.m.