i have a main-string and other sub-strings,find the sub-string which is like the main-string most. i don't know how to do it example: main-string: aqwert sub-strings: +qwerb +gfdgf +qwbt result: +qwerb : 80% ( have same qwer) +gfdgf: 0% ( nothing like) +qwbt: 20% ( have same qw) pls help me, thx