Problem description

Weird example:

S1 = fish S2 = ghoti

We can argue that ghoti is pronounced as fish in English (See: click here ):

enough: gh is pronounced as f women: o is pronounced as i potion: ti is pronounced as sh

Classes of algorithm for matching string similarity

Classes of algorithm:

Equivalence Methods

Representatives:

Word Stemming: reduces closely related words to a basic canonical form or 'stem'.
Example:
Soundex algorithm: attempt to match strings that sound alike
Example:

Similarity ranking methods

Representatives:

Longest Common Substring (between 2 strings): the longest contiguous chain of characters shared by both strings.
The longer the common substring, the better the match between the two strings.
(Will be discussed in detail later)
Edit Distance: minimum number of edit operations that it would take to transform one string into another
(Will be discussed in detail later)

The Soundex Algorithm

Soundex encoding algorithm:

The first letter of the word is the letter of the Soundex code
The first letter is not coded to a number.

Consonants are coded as follows:

Additional encoding rules:

Two adjacent letters from the same group are coded as a single number.
2 letters from the same group separated by an h or w are coded as a single number.
If you run out of consonants, add ZEROs to the code