with_progress: Report on Progress while Evaluating an R Expression

In progressr: An Inclusive, Unifying API for Progress Updates

Report on Progress while Evaluating an R Expression

Description

Report on Progress while Evaluating an R Expression

Usage

with_progress(
  expr,
  handlers = progressr::handlers(),
  cleanup = TRUE,
  delay_terminal = NULL,
  delay_stdout = NULL,
  delay_conditions = NULL,
  interrupts = getOption("progressr.interrupts", TRUE),
  interval = NULL,
  enable = NULL
)

without_progress(expr)

Arguments

expr	An R expression to evaluate.
handlers	A progression handler or a list of them. If NULL or an empty list, progress updates are ignored.
cleanup	If TRUE, all progression handlers will be shutdown at the end regardless of the progression is complete or not.
delay_terminal	If TRUE, output and conditions that may end up in the terminal will delayed.
delay_stdout	If TRUE, standard output is captured and relayed at the end just before any captured conditions are relayed.
delay_conditions	A character vector specifying base::condition classes to be captured and relayed at the end after any captured standard output is relayed.
interrupts	Controls whether interrupts should be detected or not. If TRUE and a interrupt is signaled, progress handlers are asked to report on the current amount progress when the evaluation was terminated by the interrupt, e.g. when a user pressed Ctrl-C in an interactive session, or a batch process was interrupted because it ran out of time. Note that it's optional for a progress handler to support this and only some do.
interval	(numeric) The minimum time (in seconds) between successive progression updates from handlers.
enable	(logical) If FALSE, then progress is not reported. The default is to report progress in interactive mode but not batch mode. See below for more details.

Details

If the global progression handler is enabled, it is temporarily disabled while evaluating the expr expression.

IMPORTANT: This function is meant for end users only. It should not be used by R packages, which only task is to signal progress updates, not to decide if, when, and how progress should be reported.

without_progress() evaluates an expression while ignoring all progress updates.

Value

Returns the value of the expression.

Progression handler functions

Formally, progression handlers are calling handlers that are called when a progression condition is signaled. These handlers are functions that takes one argument which is the progression condition.

Progress updates in batch mode

When running R from the command line, R runs in a non-interactive mode (interactive() returns FALSE). The default behavior of with_progress() is to not report on progress in non-interactive mode. To have progress being reported on also then, set R options progressr.enable or environment variable R_PROGRESSR_ENABLE to TRUE. Alternatively, one can set argument enable=TRUE when calling with_progress(). For example,

$ Rscript -e "library(progressr)" -e "with_progress(slow_sum(1:5))"

will not report on progress, whereas:

$ export R_PROGRESSR_ENABLE=TRUE
$ Rscript -e "library(progressr)" -e "with_progress(slow_sum(1:5))"

will.

See Also

base::withCallingHandlers()

Examples

## The slow_sum() example function
slow_sum <- progressr::slow_sum
print(slow_sum)

x <- 1:10

## Without progress updates
y <- slow_sum(x)


## Progress reported via txtProgressBar (default)
handlers("txtprogressbar")  ## default
with_progress({
  y <- slow_sum(x)
})

## Progress reported via tcltk::tkProgressBar
if (capabilities("tcltk") && requireNamespace("tcltk", quietly = TRUE)) {
  handlers("tkprogressbar")
  with_progress({
    y <- slow_sum(x)
  })
}

## Progress reported via progress::progress_bar)
if (requireNamespace("progress", quietly = TRUE)) {
  handlers("progress")
  with_progress({
    y <- slow_sum(x)
  })
}

## Progress reported via txtProgressBar and beepr::beep
if (requireNamespace("beepr", quietly = TRUE)) {
  handlers("beepr", "txtprogressbar")
  with_progress({
    y <- slow_sum(x)
  })
}

## Progress reported via customized utils::txtProgressBar and beepr::beep,
## if available.
handlers(handler_txtprogressbar(style = 3L))
if (requireNamespace("beepr", quietly = TRUE)) {
  handlers("beepr", append = TRUE)
}

with_progress({
  y <- slow_sum(1:30)
})

progressr documentation built on Aug. 11, 2023, 1:07 a.m.