| PackageDescription | String::Approx lets you match and substitute strings approximately. With
this you can emulate errors: typing errorrs, speling errors, closely
related vocabularies (colour color), genetic mutations (GAG ACT),
abbreviations (McScot, MacScot).
NOTE: String::Approx suits the task of *string matching*, not *string
comparison*, and it works for *strings*, not for *text*.
If you want to compare strings for similarity, you probably just want the
Levenshtein edit distance (explained below), the Text::Levenshtein and
Text::LevenshteinXS modules in CPAN. See also Text::WagnerFischer and
Text::PhraseDistance. (There are functions for this in String::Approx, e.g.
adist(), but their results sometimes differ from the bare Levenshtein et
al.)
If you want to compare things like text or source code, consisting of
*words* or *tokens* and *phrases* and *sentences*, or *expressions* and
*statements*, you should probably use some other tool than String::Approx,
like for example the standard UNIX diff(1) tool, or the Algorithm::Diff
module from CPAN.
The measure of *approximateness* is the _Levenshtein edit distance_. It is
the total number of "edits": insertions,
word world
deletions,
monkey money
and substitutions
sun fun
required to transform a string to another string. For example, to transform
_"lead"_ into _"gold"_, you need three edits:
lead gead goad gold
The edit distance of "lead" and "gold" is therefore three, or 75%.
*String::Approx* uses the Levenshtein edit distance as its measure, but
String::Approx is not well-suited for comparing strings of different
length, in other words, if you want a "fuzzy eq", see above. String::Approx
is more like regular expressions or index(), it finds substrings that are
close matches.> |