glue (version 1.3.1)

glue: 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", .transformer = identity_transformer,
  .trim = TRUE)
glue(..., .sep = "", .envir = parent.frame(), .open = "{",
  .close = "}", .na = "NA", .transformer = identity_transformer)

Arguments

.x

[listish] An environment, list or data frame used to lookup values.

...

[expressions] Expressions string(s) to format, multiple inputs are concatenated together before formatting.

.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.

.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.

.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.

See Also

https://www.python.org/dev/peps/pep-0498/ and https://www.python.org/dev/peps/pep-0257 upon which this is based.

Examples

# NOT RUN {
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_data()` is useful in magrittr pipes
library(magrittr)
mtcars %>% glue_data("{rownames(.)} has {hp} hp")

# Or within dplyr pipelines
library(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 = ">>")
# }