find a string with at least n matching elements

Question

I have a list of numbers that I want to find at least 3 of... here is an example

I have a large list of numbers in a sql database in the format of (for example)

01-02-03-04-05-06
06-08-19-24-25-36

etc etc basically 6 random numbers between 0 and 99.

Now I want to find the strings where at least 3 of a set of given numbers occurs. For example:

given: 01-02-03-10-11-12 return the strings that have at least 3 of those numbers in them. eg

01-05-06-09-10-12 would match
03-08-10-12-18-22 would match
03-09-12-18-22-38 would not

I am thinking that there might be some algorithm or even regular expression that could match this... but my lack of computer science textbook experience is tripping me up I think.

No - this is not a homework question! This is for an actual application!

I am developing in ruby, but any language answer would be appreciated

Answer 1

You can use a string replacement to replace - with | to turn 01-02-03-10-11-12 into 01|02|03|10|11|12. Then wrap it like this:

((01|02|03|10|11|12).*){3}

This will find any of the digit pairs, then ignore any number of characters... 3 times. If it matches, then success.