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Display or execute a snippet of R code

Source: R/snippet.R
snippet.Rd

This command will display and/or execute small snippets of R code from the book Foundations and Applications of Statistics: An Introduction Using R.

Usage

snippet(
  name,
  eval = TRUE,
  execute = eval,
  view = !execute,
  echo = TRUE,
  ask = getOption("demo.ask"),
  verbose = getOption("verbose"),
  lib.loc = NULL,
  character.only = FALSE,
  regex = NULL,
  max.files = 10L
)

Arguments

name

name of snippet

eval

a logical. An alias for `execute`.

execute

a logical. If TRUE, snippet code is executed. (The code and the results of the execution will be visible if echo is TRUE.)

view

a logical. If TRUE, snippet code is displayed 'as is'.

echo

a logical. If TRUE, show the R input when executing.

ask

a logical (or "default") indicating if devAskNewPage(ask=TRUE) should be called before graphical output happens from the snippet code. The value "default" (the factory-fresh default) means to ask if echo == TRUE and the graphics device appears to be interactive. This parameter applies both to any currently opened device and to any devices opened by the demo code. If this is evaluated to TRUE and the session is interactive, the user is asked to press RETURN to start.

verbose

a logical. If TRUE, additional diagnostics are printed.

lib.loc

character vector of directory names of R libraries, or NULL. The default value of NULL corresponds to all libraries currently known.

character.only

logical. If TRUE, use nameas character string.

regex

ignored. Retained for backwards compatibility.

max.files

an integer limiting the number of files retrieved.

Details

snippet works much like demo, but the interface is simplified. Partial matching is used to select snippets, so any unique prefix is sufficient to specify a snippet. Sequenced snippets (identified by trailing 2-digit numbers) will be executed in sequence if a unique prefix to the non-numeric portion is given. To run just one of a sequence of snippets, provide the full snippet name. See the examples.

See also

demo, source.

Author

Randall Pruim

Examples

snippet("normal01")
#> Error in snippet("normal01"): No snippet matching 'normal01'
# prefix works
snippet("normal")
#> Error in snippet("normal"): No snippet matching 'normal'
# this prefix is ambiguous
snippet("norm")
#> Multiple matches found for `norm': 
#>   normal, normal-grid, normal-loglik, normal-mle
# sequence of "histogram" snippets
snippet("hist", eval = FALSE, echo = TRUE, view = FALSE)
#> Error in snippet("hist", eval = FALSE, echo = TRUE, view = FALSE): No snippet matching 'hist'
# just one of the "histogram" snippets
snippet("histogram04", eval = FALSE, echo = TRUE, view = FALSE)
#> Error in snippet("histogram04", eval = FALSE, echo = TRUE, view = FALSE): No snippet matching 'histogram04'
# Prefix too short, but a helpful message is displayed
snippet("h", eval = FALSE, echo = TRUE, view = FALSE)
#> Multiple matches found for `h': 
#>   hatvalues, heavy-tails, helium-footballs, help, histogram, hugo