def get_sample_cats(pmf, category):
 return {k: pmf[k][category] for k in pmf if (pmf[k][category] != '')}

def get_sample_cats ( pmf , category ) : return { k : pmf [ k ] [ category ] for k in pmf if ( pmf [ k ] [ category ] != '' ) }
create {sampleid:category_value} for samples in parsed mf dict .