get_prefixes

Extracts prefixes from text. You can specify the minimum and maximum number of characters of prefixes you want.

Returns a reference to a hash, where the specified limits are mapped in hashes; each of those hashes maps every prefix in the text into the number of times it was found.

By default, both minimum and maximum limits are 3. If the minimum limit is greater than the lower one, an empty hash is returned.

A prefix is considered to be a sequence of word characters (\w) in the beginning of a word (that is, after a word boundary) that does not reach the end of the word ("regular expressionly", a prefix is the $1 of /\b(\w+)\w/).

  # extracting prefixes of size 3
  $prefixes = get_prefixes( $text );
  # extracting prefixes of sizes 2 and 3
  $prefixes = get_prefixes( {min => 2}, $text );
  # extracting prefixes of sizes 3 and 4
  $prefixes = get_prefixes( {max => 4}, $text );
  # extracting prefixes of sizes 2, 3 and 4
  $prefixes = get_prefixes( {min => 2, max=> 4}, $text);

get_suffixes

The get_suffixes function is similar to the get_prefixes one. You should read the documentation for that one and than come back to this point.

A suffix is considered to be a sequence of word characters (\w) in the end of a word (that is, before a word boundary) that does not start at the beginning of the word ("regular expressionly" speaking, a suffix is the $1 of /\w(\w+)\b/).

  # extracting suffixes of size 3
  $suffixes = get_suffixes( $text );
  # extracting suffixes of sizes 2 and 3
  $suffixes = get_suffixes( {min => 2}, $text );
  # extracting suffixes of sizes 3 and 4
  $suffixes = get_suffixes( {max => 4}, $text );
  # extracting suffixes of sizes 2, 3 and 4
  $suffixes = get_suffixes( {min => 2, max=> 4}, $text);

exclude_numbers

Set to 0 if you consider numbers as part of words. Default value is 1.

  # this
  get_suffixes( {min => 1, max => 1, exclude_numbers => 0}, "Hello, but w8" );
  # returns this:
    {
      1 => {
             'o' => 1,
             't' => 1,
             '8' => 1
           }
    }

lowercase

Set to 1 to extract all prefixes in lowercase mode. Default value is 0.

ATTENTION: This does not mean that prefixes with uppercased characters won't be extracted. It means they will be extracted after being lowercased.

  # this...
  get_prefixes( {min => 2, max => 2, lowercase => 1}, "Hello, hello");
  # returns this:
    {
      2 => {
             'he' => 2
           }
    }