Comparing 2 similar strings?

[Ed Morton]

William Park wrote:

> How do you compare 2 strings, and determine how much they are "close" to
> each other?  Eg.
>     aqwerty
>     qwertyb
> are similar to each other, except for first/last char.  But, how do I
> quantify that?
> 
> I guess you can say for the above 2 strings that
>     - at max, 6 chars out of 7 are same sequence --> 85% max
> 
> But, for
>     qawerty
>     qwerbty
> max correlation is
>     - 3 chars out of 7 are the same sequence --> 42% max
> 
> (Crossposted to 3 of my favourite newsgroup.)
>

"However you like" is probably the right answer, but one way might be to 
compare their soundex encoding 
(http://foldoc.doc.ic.ac.uk/foldoc/foldoc.cgi?soundex) and figure out 
percentage difference based on comparing the numeric part.

	Ed.