ejk@uxh.cso.uiuc.edu (Ed Kubaitis) (04/07/90)
My application involves finding the beginning of articles matching articles
listed in the table of contents in machine-readable issues of a publication
intended for human readers, not programs. (The problem is that these documents
are apparently hand entered or edited so titles in the table-of-contents do not
always exactly match the titles in the text: misspellings, abreviations in one
place but not the other, different punctuation, etc.)
Here's a fuzzy match that has (so far) served well. The algorithm is to
calculate the ratio of two letter substrings in string A occuring anywhere
in string B to the total number of two letter substrings in the shorter of
the two strings. A ratio of 0.8 or greater empirically seems to do what
I want. You may want to change the way of dealing with differences in
lengths of the two strings, or try 3 character substrings, etc. It may not
be the best, but it's small, easy to understand, and fairly fast.
Ed Kubaitis
Computing Services Office
University of Illinois
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sub fmatch {
local($A, $B) = @_;
local($l) = (length($A) < length($B)) ? length($A) : length($B);
local($m) = 0;
local($w) = 2;
local($k);
$A eq $B && return(1.0);
$l > $w || return(0.0);
for $k(0..$l-$w) {
local($s) = substr($A, $k, $w);
#---escape r.e. characters in string A---
$s =~ s/([()[\]*|?.{}\\])/\\$1/;
$B =~ $s && $m++;
}
($m/($l-$w) > 0.80) ? 1 : 0;
}