model_to_regex: Build a regular expression to fit chosen parameters

In wfindr: Crossword, Scrabble and Anagram Solver

Description

Build a regular expression to fit chosen parameters

Usage

model_to_regex(model = "*", allow = letters, ban = character(0),
  type = "usual")

Arguments

model	pattern that a word should match. Consists of letters and unknown characters specifications. Dot . stands for unknown character. It may be followed by {...} repetition quantifier (i.e. .{n}, .{n,}, .{n,m}). Asterisk * stands for unknown number of unknown characters. See examples. By default model is set to "*".
allow	characters allowed to fill gaps in a word. Can be listed in a single string or in a vector. By default is set to letters.
ban	characters not allowed to fill gaps in a word.
type	can be "usual", "scrabble", or "anagram". Abbreviated input is allowed: e.g. "u", "s", or "a". type defines how often allowed characters can be used to fill the gaps. Say, character appears n times in allow and m times in ban. If d = n - m is less or equal to zero, whatever the type is, this character won't be used to fill the gaps. For the case when d > 0: If type is "usual" then the character is allowed to fill the gaps unlimited number of times. If type is "scrabble" then the character is allowed to fill the gaps no more than d times. If type is "anagram" then the character should be used exactly d times.

Warning

If type = "scrabble" or "anagram", output regex will contain perl-like syntax. So, to use it in grep or gsub for example, set perl parameter to TRUE.

See Also

find_word, scrabble, anagram

Examples

## Regular expression to match all the 5-letter words starting with "c".
model_to_regex("c.{4}")
## Disallow "a" and "b".
model_to_regex("c.{4}", ban = "ab")
## Allow only "a" and "b" to fill the gap.
model_to_regex("c.{4}", allow = "ab")
## Allow "a", "b", and "c", but then ban "c" (result is the same as the previous example)
model_to_regex("c.{4}", allow = "abc", ban = "c")

## Regex to match all words that start with "p" and end with "zed".
model_to_regex("p*zed")

## Regex to match all the words that can be constructed of the word "thing".
model_to_regex(allow = "thing", type = "scrabble")
## Get at lest 4-letter words.
model_to_regex(".{4,}", allow = "thing", type = "scrabble")

## Regex to match anagrams of the word "thing"
model_to_regex(allow = "thing", type = "anagram")

wfindr documentation built on May 2, 2019, 12:20 p.m.