Class: StringUtilities

• Inheritance
• Description
• Class protocol
  • edit distance
  • queries

Inheritance:

   Object
   |
   +--StringUtilities

Package:

stx:libbasic2

Category:

Collections-Text-Support

Version:

rev: 1.6 date: 2015/11/18 12:07:16

user: cg

file: StringUtilities.st directory: libbasic2

module: stx stc-classLibrary: libbasic2

Description:

some less often used algorithms have been moved to here to
make libbasic more compact.

Class protocol:

 editDistanceFrom: s1 to: s2 s: substWeight k: kbdTypoWeight c: caseWeight e: exchangeWeight i: insrtWeight

another, simpler editing distance between two strings.
See also: levenshtein

usage example(s):

'comptuer' levenshteinTo:'computer' self editDistanceFrom:'comptuer' to:'computer' s:4 k:2 c:1 e:nil i:2 'computr' levenshteinTo:'computer' self editDistanceFrom:'computr' to:'computer' s:4 k:2 c:1 e:nil i:2

 isKey: k1 nextTo: k2

return true, if k1 and k2 are adjacent keys on the keyboard.
This is used to specially priorize plausible typing errors of adjacent keys.

usage example(s):

self isKey:$a nextTo:$a self isKey:$a nextTo:$s self isKey:$a nextTo:$q self isKey:$a nextTo:$w self isKey:$a nextTo:$y self isKey:$a nextTo:$z self isKey:$a nextTo:$x

 isKey: k1 nextTo: k2 onKeyboard: keys

return true, if k1 and k2 are adjacent keys on the keyboard defined by keys

usage example(s):

self isKey:$a nextTo:$q onKeyboard:(StringUtilities keyboardLayoutForLanguage:#de) self isKey:$a nextTo:$x onKeyboard:(StringUtilities keyboardLayoutForLanguage:#de)

 keyboardLayout

the keyboard layout (used with algorithms to find possible typing errors,
for example: edit distance in levenshtein)

usage example(s):

self keyboardLayout

 keyboardLayoutForLanguage: lang

the keyboard layout (used with algorithms to find possible typing errors,
for example: edit distance in levenshtein).
CAVEAT: hard coded us- and german keyboards here - should go into resource file.

usage example(s):

self keyboardLayoutForLanguage:#de

 levenshteinDistanceFrom: string1 to: string2 s: substWeight k: kbdTypoWeight c: caseWeight e: exchangeWeight i: insrtWeight d: deleteWeight

parametrized levenshtein.
return the levenshtein distance of two strings;
this value corrensponds to the number of replacements that have to be
made to get string2 from string1. The smaller the returned number,
tbe more similar are the two strings.

The arguments are the costs for
s:substitution,
k:keyboard type (substitution), if nil, s is used
c:case-change, if nil, s is used
i:insertion
d:deletion
e:exchange if nil, s*2 is used
of a character.
See IEEE transactions on Computers 1976 Pg 172 ff.

usage example(s):

'comptuer' levenshteinTo:'computer' self levenshteinDistanceFrom:'comptuer' to:'computer' s:4 k:2 c:1 e:nil i:2 d:6

 isUtilityClass