Class: Babushka::Spell

Inherits:
Object show all
Defined in:
lib/babushka/spell.rb

Class Method Summary collapse

Class Method Details

.for(string, choices:) ⇒ Object

Return a new array containing the terms from this array that were determined to be ‘similar to’ string. A string is considered to be similar to another if its Levenshtein distance is less than either the string’s length minus one, or one fifth is length plus two, whichever is less.

  word length  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  …
typos allowed  0  0  1  2  3  3  3  3  3   4   4   4   4   4   5  …

This means that:

- a little over one fifth of strings longer than 4 characters can be misspelt;
- strings 3 or 4 characters long can have 1 or 2 misspelt characters respectively;
- strings 1 or 2 characters long must be spelt correctly.



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# File 'lib/babushka/spell.rb', line 17

def self.for(string, choices:)
  choices.map {|term|
    [term, Babushka::Levenshtein.distance(term, string)]
  }.select {|(i, similarity)|
    similarity <= [i.length - 2, (i.length / 5) + 2].min
  }.sort_by {|(_, similarity)|
    similarity
  }.map {|(i, _)|
    i
  }
end