COMPLEV Function

Compares two strings by computing the Levenshtein edit distance

Category: Character

Syntax

COMPLEV ( string-1 , string-2 <, cutoff ><, modifiers >)

Arguments

string-1

specifies a character constant, variable, or expression.

string-2

specifies a character constant, variable, or expression.

cuttoff

specifies a numeric constant, variable, or expression. If the acutal Levenshtein edit distance is greater than the value of cutoff , the value that is returned is equal to the value of cutoff .
Tip: Using a small value of cutoff improves the efficiency of COMPGED if the values of string-1 and string-2 are long.

modifiers

specifies a character string that can modify the action of the COMPLEV function. You can use one or more of the following characters as a valid modifier:

i or I	ignores the case in string-1 and string-2 .
l or L	removes leading blanks in string-1 and string-2 before comparing the values.
n or N	removes quotation marks from any argument that is an n-literal and ignores the case of string-1 and string-2 .
: ( colon )	truncates the longer of string-1 or string-2 to the length of the shorter string, or to one, whichever is greater.

TIP: COMPLEV ignores blanks that are used as modifiers.

Details

The order in which the modifiers appear in the COMPLEV function is relevant.

'LN' first removes leading blanks from each string and then removes quotation marks from n-literals.
'NL' first removes quotation marks from n-literals and then removes leading blanks from each string.

The COMPLEV function ignores trailing blanks.

COMPLEV returns the Levenshtein edit distance between string-1 and string-2 . Levenshtein edit distance is the number of insertions, deletions, or replacements of single characters that are required to convert one string to the other. Levenshtein edit distance is symmetric. That is, COMPLEV(string-1,string-2) is the same as COMPLEV(string-2,string-1) .

Comparisons

The Levenshtein edit distance that is computed by COMPLEV is a special case of the generalized edit distance that is computed by COMPGED.

COMPLEV executes much more quickly than COMPGED.

Examples

The following example compares two strings by computing the Levenshtein edit distance.

 options pageno=1 nodate ls=80 ps=60;  data test;     infile datalines missover;     input string1 $char8. string2 $char8. modifiers $char8.;     result=complev(string1, string2, modifiers);     datalines;  1234567812345678  abc     abxc  ac      abc  aXc     abc  aXbZc   abc  aXYZc   abc  WaXbYcZ abc  XYZ     abcdef  aBc     abc  aBc     AbC        i    abc   abc    abc   abc        l  AxC     'abc'n  AxC     'abc'n     n  ;  proc print data=test;  run;

The following output shows the results.

Output 4.22: Results of Comparing Two Strings by Computing the Levenshtein Edit Distance

 The SAS System                                  1   Obs    string1     string2      modifiers    result     1    12345678    12345678                     0     2    abc         abxc                         1     3    ac          abc                          1     4    aXc         abc                          1     5    aXbZc       abc                          2     6    aXYZc       abc                          3     7    WaXbYcZ     abc                          4     8    XYZ         abcdef                       6     9    aBc         abc                          1    10    aBc         AbC              i           0    11      abc       abc                          2    12      abc       abc              l           0    13    AxC         'abc'n                       6    14    AxC         'abc'n           n           1

COMPLEV Function