renderText
renderText(expr, env = parent.frame(), quoted = FALSE, func = NULL)
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. |
func | A function that returns an R object that can be used as an
argument to cat .(deprecated; use expr instead). |
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.