explain() R function from [qdapRegex]

Visualize Regular Expressions

Visualize regular expressions using https://regexper.com/


explain(
  pattern,
  open = FALSE,
  print = TRUE,
  dictionary = getOption("regex.library")
)

Arguments

pattern: A character string containing a regular expression or a character string starting with "@" that is a regular expression from a qdapRegex dictionary.
open: logical. If TRUE the default browser will attempt to open https://regexper.com/ page. Setting open = 2 will utilize an unstable visualization via https://www.debuggex.com. This approach utilizes a non-api scrape that is subject to change and not guaranteed to be stable. The regex is set to Python flavor which handles lookbehinds that the Java based https://regexper.com/ does not. This functionality was developed by Matthew Flickinger (see https://stackoverflow.com/a/27574103/1000343 for details). Note that the user must have httr installed or will be prompted if the package cannot be required.
print: logical. Should explain print output to the console?
dictionary: A dictionary of canned regular expressions to search within.

Returns

Prints https://regexper.com/ to the console, attempts to open the url to the visual representation provided by https://regexper.com/, and invisibly returns a list with the URLs.

Details

Note that https://regexper.com/ is a Java based regular expression viewer. Lookbehind and negative lookbehinds are not respected.

Examples


explain("\\s*foo[A-Z]\\d{2,3}")
explain("@rm_time")
## Not run:

explain("\\s*foo[A-Z]\\d{2,3}", open = TRUE)
explain("@rm_time", open = TRUE)
## End(Not run)