(PHP3 >= 3.0.7, PHP4 >= 4.0b2)

similar_text --  Calculate the similarity between two strings


int similar_text (string first, string second [, double percent])

This calculates the similarity between two strings as described in Oliver [1993]. Note that this implementation does not use a stack as in Oliver's pseudo code, but recursive calls which may or may not speed up the whole process. Note also that the complexity of this algorithm is O(N**3) where N is the length of the longest string.

By passing a reference as third argument, similar_text() will calculate the similarity in percent for you. It returns the number of matching chars in both strings.