Shiny by RStudio

Text Output

renderText(expr, env = parent.frame(), quoted = FALSE,
  outputArgs = list())

Arguments

expr An expression that returns an R object that can be used as an argument to cat.
env The environment in which to evaluate expr.
quoted Is expr a quoted expression (with quote())? This is useful if you want to save an expression in a variable.
outputArgs A list of arguments to be passed through to the implicit call to textOutput when renderText is used in an interactive R Markdown document.

Description

Makes a reactive version of the given function that also uses cat to turn its result into a single-element character vector.

Details

The corresponding HTML output tag can be anything (though pre is recommended if you need a monospace font and whitespace preserved) and should have the CSS class name shiny-text-output.

The result of executing func will passed to cat, inside a capture.output call.

Examples

isolate({ # renderPrint captures any print output, converts it to a string, and # returns it visFun <- renderPrint({ "foo" }) visFun() # '[1] "foo"' invisFun <- renderPrint({ invisible("foo") }) invisFun() # '' multiprintFun <- renderPrint({ print("foo"); "bar" }) multiprintFun() # '[1] "foo"\n[1] "bar"' nullFun <- renderPrint({ NULL }) nullFun() # 'NULL' invisNullFun <- renderPrint({ invisible(NULL) }) invisNullFun() # '' vecFun <- renderPrint({ 1:5 }) vecFun() # '[1] 1 2 3 4 5' # Contrast with renderText, which takes the value returned from the function # and uses cat() to convert it to a string visFun <- renderText({ "foo" }) visFun() # 'foo' invisFun <- renderText({ invisible("foo") }) invisFun() # 'foo' multiprintFun <- renderText({ print("foo"); "bar" }) multiprintFun() # 'bar' nullFun <- renderText({ NULL }) nullFun() # '' invisNullFun <- renderText({ invisible(NULL) }) invisNullFun() # '' vecFun <- renderText({ 1:5 }) vecFun() # '1 2 3 4 5' })
[1] "foo"
[1] "1 2 3 4 5"

See also

renderPrint for capturing the print output of a function, rather than the returned text value.