hashtable

I have an application that is accepting two .csv files as input, comparing them using employee Ids and generating two output files in excel format - new employees and removed employees. I am storing the data of input .csv files in hashtables. Storing the data in the following format-...

Can we check for a part of string in hashtable key? For example, our key is key = residentnumber +","+ housenumber I know have a function called containskey() but do we have something that could partially check for a string in a hashtable key? For example, if we could search...