phpman > perldoc > Lingua::EN::Fathom(3pm)

NAME
    Lingua::EN::Fathom - Measure readability of English text

SYNOPSIS
        use Lingua::EN::Fathom;

        my $text = Lingua::EN::Fathom->new();

        # Analyse contents of a text file
        $text->analyse_file("sample.txt"); # Analyse contents of a text file

        $accumulate = 1;
        # Analyse contents of a text string
        $text->analyse_block($text_string,$accumulate);

        # TO Do, remove repetition
        $num_chars             = $text->num_chars;
        $num_words             = $text->num_words;
        $percent_complex_words = $text->percent_complex_words;
        $num_sentences         = $text->num_sentences;
        $num_text_lines        = $text->num_text_lines;
        $num_blank_lines       = $text->num_blank_lines;
        $num_paragraphs        = $text->num_paragraphs;
        $syllables_per_word    = $text->syllables_per_word;
        $words_per_sentence    = $text->words_per_sentence;

       # comment needed
        %words = $text->unique_words;
        foreach $word ( sort keys %words )
        {
          print("$words{$word} :$word\n");
        }

        $fog     = $text->fog;
        $flesch  = $text->flesch;
        $kincaid = $text->kincaid;

        print($text->report);

REQUIRES
    Perl, version 5.001 or higher, Lingua::EN::Syllable

DESCRIPTION
    This module analyses English text in either a string or file. Totals are then calculated for the
    number of characters, words, sentences, blank and non blank (text) lines and paragraphs.

    Three common readability statistics are also derived, the Fog, Flesch and Kincaid indices.

    All of these properties can be accessed through individual methods, or by generating a text
    report.

    A hash of all unique words and the number of times they occur is generated.

METHODS
  new
    The "new" method creates an instance of an text object This must be called before any of the
    following methods are invoked. Note that the object only needs to be created once, and can be
    reused with new input data.

       my $text = Lingua::EN::Fathom->new();

  analyse_file
    The "analyse_file" method takes as input the name of a text file. Various text based statistics
    are calculated for the file. This method and "analyse_block" are prerequisites for all the
    following methods. An optional argument may be supplied to control accumulation of statistics.
    If set to a non zero value, all statistics are accumulated with each successive call.

        $text->analyse_file("sample.txt");

  analyse_block
    The "analyse_block" method takes as input a text string. Various text based statistics are
    calculated for the file. This method and "analyse_file" are prerequisites for all the following
    methods. An optional argument may be supplied to control accumulation of statistics. If set to a
    non zero value, all statistics are accumulated with each successive call.

        $text->analyse_block($text_str);

  num_chars
    Returns the number of characters in the analysed text file or block. This includes characters
    such as spaces, and punctuation marks.

  num_words
    Returns the number of words in the analysed text file or block. A word must consist of letters
    a-z with at least one vowel sound, and optionally an apostrophe or hyphen. Items such as "&,
    K108, NW" are not counted as words.

  percent_complex_words
    Returns the percentage of complex words in the analysed text file or block. A complex word must
    consist of three or more syllables. This statistic is used to calculate the fog index.

  num_sentences
    Returns the number of sentences in the analysed text file or block. A sentence is any group of
    words and non words terminated with a single full stop. Spaces may occur before and after the
    full stop.

  num_text_lines
    Returns the number of lines containing some text in the analysed text file or block.

  num_blank_lines
    Returns the number of lines NOT containing any text in the analysed text file or block.

  num_paragraphs
    Returns the number of paragraphs in the analysed text file or block.

  syllables_per_word
    Returns the average number of syllables per word in the analysed text file or block.

  words_per_sentence
    Returns the average number of words per sentence in the analysed text file or block.

  READABILITY
    Three indices of text readability are calculated. They all measure complexity as a function of
    syllables per word and words per sentence. They assume the text is well formed and logical. You
    could analyse a passage of nonsensical English and find the readability is quite good, provided
    the words are not too complex and the sentences not too long.

    For more information see: <http://www.plainlanguage.com/Resources/readability.html>

  fog
    Returns the Fog index for the analysed text file or block.

      ( words_per_sentence + percent_complex_words ) * 0.4

    The Fog index, developed by Robert Gunning, is a well known and simple formula for measuring
    readability. The index indicates the number of years of formal education a reader of average
    intelligence would need to read the text once and understand that piece of writing with its word
    sentence workload.

       18 unreadable
       14 difficult
       12 ideal
       10 acceptable
        8 childish

  flesch
    Returns the Flesch reading ease score for the analysed text file or block.

       206.835 - (1.015 * words_per_sentence) - (84.6 * syllables_per_word)

    This score rates text on a 100 point scale. The higher the score, the easier it is to understand
    the text. A score of 60 to 70 is considered to be optimal.

  kincaid
    Returns the Flesch-Kincaid grade level score for the analysed text file or block.

       (11.8 * syllables_per_word) +  (0.39 * words_per_sentence) - 15.59;

    This score rates text on U.S. grade school level. So a score of 8.0 means that the document can
    be understood by an eighth grader. A score of 7.0 to 8.0 is considered to be optimal.

  unique_words
    Returns a hash of unique words. The words (in lower case) are held in the hash keys while the
    number of occurrences are held in the hash values.

  report
        print($text->report);

    Produces a text based report containing all Fathom statistics for the currently analysed text
    block or file. For example:

    Number of characters : 813 Number of words : 135 Percent of complex words : 20.00 Average
    syllables per word : 1.7704 Number of sentences : 12 Average words per sentence : 11.2500 Number
    of text lines : 13 Number of blank lines : 8 Number of paragraphs : 4

    READABILITY INDICES

    Fog : 12.5000 Flesch : 45.6429 Flesch-Kincaid : 9.6879

    The return value is a string containing the report contents

SEE ALSO
    Lingua::EN::Syllable,Lingua::EN::Sentence,B::Fathom

POSSIBLE EXTENSIONS
       Count white space and punctuation characters
       Allow user control over what strictly defines a word

LIMITATIONS
    The syllable count provided in Lingua::EN::Syllable is about 90% accurate

    Acronyms that contain vowels, like GPO, will be counted as words.

    The fog index should exclude proper names

BUGS
    None known

AUTHOR
    Lingua::EN::Fathom was written by Kim Ryan <kimryan at cpan dot org>.

COPYRIGHT AND LICENSE
    Copyright (c) 2018 Kim Ryan. All rights reserved.

    This library is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself.