Stack and StackList classes and methods

Description

push - Append an element.

pop - Remove and return the last element.

clear - Remove all elements.

shift - Remove and return the first element.

first_element - Return the first element. We can't use first because it's taken by the dplyr package and is not an S3 method.

last_element - Return the last element. We can't use last because it's taken by the dplyr package and is not an S3 method.

size - Return the number of elements.

as.Stack - Creates a new Stack from (typically, vector) s.

as.StackList - Creates a new StackList from (typically, list) s.

Stack() - Creates and keeps a stack of items of the same type, implemented as an R vector. The type is determined by the first push operation.

StackList() - Creates and keeps a list of items of the same type, implemented as an R list. The type is determined by the first push operation.

Usage

push(x, value)

pop(x)

clear(x)

shift(x)

first_element(x)

last_element(x)

size(x)

as.Stack(s)

as.StackList(s)

Stack()

StackList()

Arguments

Timing utilities.

Description

tic - Starts the timer and stores the start time and the message on the stack.

toc - Notes the current timer and computes elapsed time since the matching call to tic(). When quiet is FALSE, prints the associated message and the elapsed time.

toc.outmsg - Formats a message for pretty printing. Redefine this for different formatting.

tic.clearlog - Clears the tic/toc log.

tic.clear - Clears the tic/toc stack. This could be useful in cases when because of an error the closing toc() calls never get executed.

tic.log - Returns log messages from calls to tic/toc since the last call to tic.clearlog.

Usage

tic(msg = NULL, quiet = TRUE, func.tic = NULL, ...)

toc(log = FALSE, quiet = FALSE, func.toc = toc.outmsg, ...)

toc.outmsg(tic, toc, msg)

tic.clearlog()

tic.clear()

tic.log(format = TRUE)

Arguments

Value

tic returns the timestamp (invisible).

toc returns an (invisible) list containing the timestamps tic, toc, and the message msg.

toc.outmsg returns formatted message.

tic.log returns a list of formatted messages (format = TRUE) or a list of lists containing the timestamps and unformatted messages from prior calls to tic/toc.

See Also

tictoc, Stack

Examples

## Not run: 

## Basic use case
tic()
print("Do something...")
Sys.sleep(1)
toc()
# 1.034 sec elapsed

## Inline timing example, similar to system.time()
tic(); for(i in 1:1000000) { j = i / 2 }; toc()
# 0.527 sec elapsed

## Timing multiple steps
tic("step 1")
print("Do something...")
Sys.sleep(1)
toc()
# step 1: 1.005 sec elapsed

tic("step 2")
print("Do something...")
Sys.sleep(1)
toc()
# step 2: 1.004 sec elapsed

## Timing nested code
tic("outer")
   Sys.sleep(1)
   tic("middle")
      Sys.sleep(2)
      tic("inner")
         Sys.sleep(3)
      toc()
# inner: 3.004 sec elapsed
   toc()
# middle: 5.008 sec elapsed
toc()
# outer: 6.016 sec elapsed

## Timing in a loop and analyzing the results later using tic.log().
tic.clearlog()
for (x in 1:10)
{
   tic(x)
   Sys.sleep(1)
   toc(log = TRUE, quiet = TRUE)
}
log.txt <- tic.log(format = TRUE)
log.lst <- tic.log(format = FALSE)
tic.clearlog()

timings <- unlist(lapply(log.lst, function(x) x$toc - x$tic))
mean(timings)
# [1] 1.001
writeLines(unlist(log.txt))
# 1: 1.002 sec elapsed
# 2: 1 sec elapsed
# 3: 1.002 sec elapsed
# 4: 1.001 sec elapsed
# 5: 1.001 sec elapsed
# 6: 1.001 sec elapsed
# 7: 1.001 sec elapsed
# 8: 1.001 sec elapsed
# 9: 1.001 sec elapsed
# 10: 1 sec elapsed

## Using custom callbacks in tic/toc
my.msg.tic <- function(tic, msg)
{
   if (is.null(msg) || is.na(msg) || length(msg) == 0)
   {
      outmsg <- paste0(round(toc - tic, 3), " seconds elapsed")
   }
   else
   {
      outmsg <- paste0("Starting ", msg, "...")
   }
   outmsg
}

my.msg.toc <- function(tic, toc, msg, info)
{
   if (is.null(msg) || is.na(msg) || length(msg) == 0)
   {
      outmsg <- paste0(round(toc - tic, 3), " seconds elapsed")
   }
   else
   {
      outmsg <- paste0(info, ": ", msg, ": ",
                   round(toc - tic, 3), " seconds elapsed")
   }
   outmsg
}

tic("outer", quiet = FALSE, func.tic = my.msg.tic)
# Starting outer...
   Sys.sleep(1)
   tic("middle", quiet = FALSE, func.tic = my.msg.tic)
# Starting middle...
      Sys.sleep(2)
      tic("inner", quiet = FALSE, func.tic = my.msg.tic)
         Sys.sleep(3)
# Starting inner...
      toc(quiet = FALSE, func.toc = my.msg.toc, info = "INFO")
# INFO: inner: 3.005 seconds elapsed
   toc(quiet = FALSE, func.toc = my.msg.toc, info = "INFO")
# INFO: middle: 5.01 seconds elapsed
toc(quiet = FALSE, func.toc = my.msg.toc, info = "INFO")
# INFO: outer: 6.014 seconds elapsed


## End(Not run)

Package tictoc.

Description

Functions for timing, as well as implementations of Stack and StackList structures.

Details

The tictoc package provides the timing functions tic and toc that can be nested. It provides an alternative to system.time() with a different syntax similar to that in another well-known software package. tic and toc are easy to use, and are especially useful when timing several sections in more than a few lines of code.

In general, calls to tic and toc start the timer when the tic call is made and stop the timer when the toc call is made, recording the elapsed time between the calls from proc.time. The default behavior is to print a simple message with the elapsed time in the toc call.

The features include the following:

• nesting of the tic and toc calls

• suppressing the default output with quiet = TRUE

• collecting the timings in user-defined variables

• collecting the timings in a log structure provided by the package (see tic.log)

• providing a custom message for each tic call

• using custom callbacks for the tic and toc calls to redefine the default behavior and/or add other functionality (such as logging to a database)

In addition, this package provides classes Stack (implemented as a vector) and StackList (a stack implemented as a list), both of which support operations push, pop, first_element, last_element, clear and size.

Copyright

Copyright (C) Collective, Inc.; with portions Copyright (C) Jabiru Ventures LLC

License

Apache License, Version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0

URL

http://github.com/jabiru/tictoc

Installation from github

devtools::install_github("jabiru/tictoc")

Author(s)

Sergei Izrailev

See Also

tic, Stack