renderPrint
Printable Output
Makes a reactive version of the given function that captures any printed
output, and also captures its printable result (unless
base::invisible()
), into a string. The resulting function is suitable
for assigning to an output
slot.
Usage
renderPrint(
expr,
env = parent.frame(),
quoted = FALSE,
width = getOption("width"),
outputArgs = list()
)
Arguments
- expr
An expression that may print output and/or return a printable R object.
- env
The environment in which to evaluate
expr
.- quoted
Is
expr
a quoted expression (withquote()
)? This is useful if you want to save an expression in a variable.- width
The value for
[options][base::options]('width')
.- outputArgs
A list of arguments to be passed through to the implicit call to
verbatimTextOutput()
whenrenderPrint
is used in an interactive R Markdown document.
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 be printed inside a
utils::capture.output()
call.
Note that unlike most other Shiny output functions, if the given function
returns NULL
then NULL
will actually be visible in the output.
To display nothing, make your function return base::invisible()
.
See Also
renderText()
for displaying the value returned from a
function, instead of the printed output.
Examples
# NOT RUN {
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'
})
# }