Java – Mahout: To read a custom input file

I was playing with Mahout and found that FileDataModel accepts data in the following format

     userId,itemId,pref(long,long,Double).

I have some data in format

     String,long,double 

What is the best/easiest way to use this dataset on Mahout?

One way is to create Extension of FileDataModel. You need to override readUserIDFromString(String value) A method that uses some kind of parser to convert. You can use IDMigrator One of the implementations. , as Sean suggested.

For example, suppose you have an initialized one MemoryIDMigrator , you can do this:

@Override
protected long readUserIDFromString(String stringID) {
    long result = memoryIDMigrator.toLongID(stringID); 
    memoryIDMigrator.storeMapping(result, stringID);
    return result;
}

This way you can also use memoryIDMigrator for reverse mapping. If you don’t need it, you can hash it the way it is in your implementation (in AbstractIDMigrator 中).