Progress bar in the terminal — progress

Progress bars are configurable, may include percentage, elapsed time, and/or the estimated completion time. They work in the command line, in Emacs and in R Studio. The progress package was heavily influenced by https://github.com/tj/node-progress

Creating the progress bar

A progress bar is an R6 object, that can be created with progress_bar$new(). It has the following arguments:

format: The format of the progress bar. A number of tokens can be used here, see them below. It defaults to "[:bar] :percent", which means that the progress bar is within brackets on the left, and the percentage is printed on the right.
total: Total number of ticks to complete. If it is unknown, use NA here. Defaults to 100.
width: Width of the progress bar. Default is the current terminal width (see options() and width) minus two.
stream: This argument is deprecated, and message() is used to print the progress bar.
complete: Completion character, defaults to =.
incomplete: Incomplete character, defaults to -.
current: Current character, defaults to >.
callback: Callback function to call when the progress bar finishes. The progress bar object itself is passed to it as the single parameter.
clear: Whether to clear the progress bar on completion. Defaults to TRUE.
show_after: Amount of time in seconds, after which the progress bar is shown on the screen. For very short processes, it is probably not worth showing it at all. Defaults to two tenth of a second.
force: Whether to force showing the progress bar, even if the given (or default) stream does not seem to support it.
message_class: Extra classes to add to the message conditions signalled by the progress bar.

Using the progress bar

Three functions can update a progress bar. progress_bar$tick() increases the number of ticks by one (or another specified value). progress_bar$update() sets a given ratio and progress_bar$terminate() removes the progress bar. progress_bar$finished can be used to see if the progress bar has finished.

Note that the progress bar is not shown immediately, but only after show_after seconds. (Set this to zero, and call tick(0) to force showing the progress bar.)

progress_bar$message() prints a message above the progress bar. It fails if the progress bar has already finished.

Tokens

They can be used in the format argument when creating the progress bar.

:bar: The progress bar itself.
:current: Current tick number.
:total: Total ticks.
:elapsed: Elapsed time in seconds.
:elapsedfull: Elapsed time in hh:mm:ss format.
:eta: Estimated completion time in seconds.
:percent: Completion percentage.
:rate: Download rate, bytes per second. See example below.
:tick_rate: Similar to :rate, but we don't assume that the units are bytes, we just print the raw number of ticks per second.
:bytes: Shows :current, formatted as bytes. Useful for downloads or file reads if you don't know the size of the file in advance. See example below.
:spin: Shows a spinner that updates even when progress is advanced by zero.

Custom tokens are also supported, and you need to pass their values to progress_bar$tick() or progress_bar$update(), in a named list. See example below.

Options

The progress_enabled option can be set to FALSE to turn off the progress bar. This works for the C++ progress bar as well.

Examples


## We don't run the examples on CRAN, because they takes >10s
## altogether. Unfortunately it is hard to create a set of
## meaningful progress bar examples that also run quickly.
if (FALSE) {

## Basic
pb <- progress_bar$new(total = 100)
for (i in 1:100) {
  pb$tick()
  Sys.sleep(1 / 100)
}

## ETA
pb <- progress_bar$new(
  format = "  downloading [:bar] :percent eta: :eta",
  total = 100, clear = FALSE, width= 60)
for (i in 1:100) {
  pb$tick()
  Sys.sleep(1 / 100)
}

## Elapsed time
pb <- progress_bar$new(
  format = "  downloading [:bar] :percent in :elapsed",
  total = 100, clear = FALSE, width= 60)
for (i in 1:100) {
  pb$tick()
  Sys.sleep(1 / 100)
}

## Spinner
pb <- progress_bar$new(
  format = "(:spin) [:bar] :percent",
  total = 30, clear = FALSE, width = 60)
for (i in 1:30) {
  pb$tick()
  Sys.sleep(3 / 100)
}

## Custom tokens
pb <- progress_bar$new(
  format = "  downloading :what [:bar] :percent eta: :eta",
  clear = FALSE, total = 200, width = 60)
f <- function() {
  for (i in 1:100) {
    pb$tick(tokens = list(what = "foo   "))
    Sys.sleep(2 / 100)
  }
  for (i in 1:100) {
    pb$tick(tokens = list(what = "foobar"))
    Sys.sleep(2 / 100)
  }
}
f()

## Download (or other) rates
pb <- progress_bar$new(
  format = "  downloading foobar at :rate, got :bytes in :elapsed",
  clear = FALSE, total = NA, width = 60)
f <- function() {
  for (i in 1:100) {
    pb$tick(sample(1:100 * 1000, 1))
    Sys.sleep(2/100)
  }
  pb$tick(1e7)
  invisible()
}
f()

pb <- progress_bar$new(
  format = "  got :current rows at :tick_rate/sec",
  clear = FALSE, total = NA, width = 60)
f <- function() {
  for (i in 1:100) {
    pb$tick(sample(1:100, 1))
    Sys.sleep(2/100)
  }
  pb$terminate()
  invisible()
}
f()

}