with_progress: Report on Progress while Evaluating an R Expression

Description Usage Arguments Details Value Progression handler functions Progress updates in batch mode See Also Examples

View source: R/with_progress.R

Description

Report on Progress while Evaluating an R Expression

Usage

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with_progress(
  expr,
  handlers = progressr::handlers(),
  cleanup = TRUE,
  delay_terminal = NULL,
  delay_stdout = NULL,
  delay_conditions = NULL,
  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.

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

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

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## 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 Sept. 24, 2021, 5:07 p.m.