SPEDIS

SPEDIS

Determines the likelihood of two words matching, expressed as the asymmetric spelling distance between the two words

Category: Character

Syntax
Arguments
Details
Examples

Syntax

SPEDIS(query,keyword)

Arguments

query: identifies the word to query for the likelihood of a match. SPEDIS removes trailing blanks before comparing the value.
keyword: specifies a target word for the query. SPEDIS removes trailing blanks before comparing the value.

Details

SPEDIS returns the distance between the query and a keyword, a nonnegative value usually less than 100, never greater than 200 with the default costs.

SPEDIS computes an asymmetric spelling distance between two words as the normalized cost for converting the keyword to the query word via a sequence of operations. SPEDIS(QUERY, KEYWORD) is NOT the same as SPEDIS(KEYWORD, QUERY).

Costs for each operation that is required to convert the keyword to the query are

Operation Cost Explanation

match 0 no change

singlet 25 delete one of a double letter

doublet 50 double a letter

swap 50 reverse the order of two consecutive letters

truncate 50 delete a letter from the end

append 35 add a letter to the end

delete 50 delete a letter from the middle

insert 100 insert a letter in the middle

replace 100 replace a letter in the middle

firstdel 100 delete the first letter

firstins 200 insert a letter at the beginning

firstrep 200 replace the first letter

Operation	Cost	Explanation
match	0	no change
singlet	25	delete one of a double letter
doublet	50	double a letter
swap	50	reverse the order of two consecutive letters
truncate	50	delete a letter from the end
append	35	add a letter to the end
delete	50	delete a letter from the middle
insert	100	insert a letter in the middle
replace	100	replace a letter in the middle
firstdel	100	delete the first letter
firstins	200	insert a letter at the beginning
firstrep	200	replace the first letter

The distance is the sum of the costs divided (in integer arithmetic) by the length of the query.

Examples

options nodate pageno=1 linesize=64;
data words;
   input oper $ query $ keyword $;
   dist = spedis(query,keyword);
   cost = dist * length(query);
   put oper $10. query $10. keyword $10. 
       dist 5. cost 5.;
datalines;
match       fuzzy        fuzzy
singlet     fuzy         fuzzy
doublet     fuuzzy       fuzzy
swap        fzuzy        fuzzy
truncate    fuzz         fuzzy
append      fuzzys       fuzzy
delete      fzzy         fuzzy
insert      fluzzy       fuzzy
replace     fizzy        fuzzy
firstdel    uzzy         fuzzy
firstins    pfuzzy       fuzzy
firstrep    wuzzy        fuzzy
several     floozy       fuzzy
;

proc print data = words;
run;

The output from the DATA step is as follows:

The SAS System 1 OBS OPER QUERY KEYWORD DIST COST 1 match fuzzy fuzzy 0 0 2 singlet fuzy fuzzy 6 24 3 doublet fuuzzy fuzzy 8 48 4 swap fzuzy fuzzy 10 50 5 truncate fuzz fuzzy 12 48 6 append fuzzys fuzzy 5 30 7 delete fzzy fuzzy 12 48 8 insert fluzzy fuzzy 16 96 9 replace fizzy fuzzy 20 100 10 firstdel uzzy fuzzy 25 100 11 firstins pfuzzy fuzzy 33 198 12 firstrep wuzzy fuzzy 40 200 13 several floozy fuzzy 50 300

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