R.utils (version 2.12.3)

TextStatusBar: A status bar at the R prompt that can be updated

Description

Package: R.utils
Class TextStatusBar

Object
~~|
~~+--TextStatusBar

Directly known subclasses:

public static class TextStatusBar
extends Object

A status bar at the R prompt that can be updated.

Usage

TextStatusBar(fmt=paste("%-", getOption("width") - 1, "s", sep = ""), ...)

Arguments

fmt

A character format string to be used by sprintf(). Default is a left-aligned string of full width.

...

Named arguments to be passed to sprintf() together with the format string.

Fields and Methods

Methods:

	flush	-
	getLabel	-
	newline	-
	popMessage	-
	setLabel	-
	setLabels	-
	update	-
	updateLabels	-

Methods inherited from Object:
$, $<-, [[, [[<-, as.character, attach, attachLocally, clearCache, clearLookupCache, clone, detach, equals, extend, finalize, getEnvironment, getFieldModifier, getFieldModifiers, getFields, getInstantiationTime, getStaticInstance, hasField, hashCode, ll, load, names, objectSize, print, save

Author

Henrik Bengtsson

Details

A label with name hfill can be used for automatic horizontal filling. It must be numeric and be immediate before a string label such that a hfill label and the following string label together specifies an sprintf format such as "%*-s". The value of hfill will be set such that the resulting status bar has width equal to getOption("width")-1 (the reason for the -1 is to prevent the text status bar from writing into the next line). If more than one hfill label is used their widths will be uniformly distributed. Left over spaces will be distributed between hfill labels with initial values of one.

Examples

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Read all HTML files in the base package
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
path <- system.file(package="base")
files <- list.files(path, recursive=TRUE, full.names=TRUE)
files <- files[sapply(files, FUN=isFile)]
nfiles <- length(files)

cat(sprintf("Reading %d files in %s:\n", nfiles, path))

# Create a status bar with four labels
sb <- TextStatusBar("File: %-*s [%3.0f%% %7.0f bytes %-8s]",
                hfill=1, file="", progress=0, nbytes=0L, time="")

nbytes <- 0L
for (kk in seq_len(nfiles)) {
  file <- files[kk]

  # Update the status bar
  if (sb) {
    setLabel(sb, "progress", 100*kk/nfiles)
    if (kk %% 10 == 1 || kk == nfiles)
      setLabel(sb, "file", substr(basename(file), 1, 44))

    size <- file.info(file)$size
    # popMessage() calls update() too
    popMessage(sb, sprintf("Processing %s (%.2fkB)",
                                       basename(file), size/1024))
    flush(sb)
  }

  # Read the file
  bfr <- readBin(file, what="raw", n=size)
  nbytes <- nbytes + size

  # Emulate a slow process
  if (interactive()) Sys.sleep(rexp(1, rate=60))

  # Update the status bar
  if (sb) {
    setLabel(sb, "nbytes", nbytes)
    setLabel(sb, "time", format(Sys.time(), "%H:%M:%S"))
    update(sb)
  }
}
setLabel(sb, "file", "")
update(sb)
cat("\n")