Text Templates in R Programming Language
R offers several packages for creating dynamic content or showing customized output to the user. While there isn’t a direct equivalent to Go’s text/template
package, we can achieve similar functionality using R’s string manipulation and evaluation capabilities.
library(glue)
main <- function() {
# We can create a string template using glue
# Expressions inside {} will be evaluated and inserted
t1 <- "Value is {.}\n"
# We can use glue to insert values into the template
cat(glue(t1, "some text"))
cat(glue(t1, 5))
cat(glue(t1, c("R", "Python", "Julia", "Scala")))
# Helper function to create a template
create <- function(name, t) {
function(...) cat(glue(t, ...))
}
# If the data is a list, we can access its elements by name
t2 <- create("t2", "Name: {.name}\n")
t2(list(name = "Jane Doe"))
# The same applies to named vectors
t2(c(name = "Mickey Mouse"))
# Conditional execution can be achieved using ifelse
t3 <- create("t3", "{ifelse(nchar(.) > 0, 'yes', 'no')}\n")
t3("not empty")
t3("")
# We can use lapply or sapply for iteration
t4 <- create("t4", "Range: {paste(., collapse = ' ')}\n")
t4(c("R", "Python", "Julia", "Scala"))
}
main()
To run the program, save it as templates.R
and use Rscript
:
$ Rscript templates.R
Value is some text
Value is 5
Value is c("R", "Python", "Julia", "Scala")
Name: Jane Doe
Name: Mickey Mouse
yes
no
Range: R Python Julia Scala
In this R version:
We use the
glue
package for string interpolation, which is similar to Go’s template syntax.Instead of creating formal Template objects, we use functions that return formatted strings.
The
create
function returns a new function that applies the template to its arguments.For conditional execution, we use R’s
ifelse
function instead of a template-specific syntax.For iteration, we use R’s vector operations and
paste
function to join elements.
While this approach doesn’t provide all the features of Go’s templating system, it demonstrates how to achieve similar functionality in R using built-in features and common packages.