datasets["comp_set"]

means = datasets["comp_set"].groupby(['DAYS_SINCE_RELEASE','STOREID'], as_index=False).UNITS.mean()
means.columns = ['DAYS_SINCE_RELEASE', 'STOREID', 'COMP_AVG_UNITS']
#print means

my_release = datasets["my_release"][['DAYS_SINCE_RELEASE', 'STOREID', 'UNITS']]
my_release.columns = ['DAYS_SINCE_RELEASE', 'STOREID', 'RELEASE_UNITS']

#print my_release

comparison = pd.merge(my_release,means, on=['DAYS_SINCE_RELEASE', 'STOREID'])

comparison['BENCHMARK'] = (comparison['RELEASE_UNITS'] - comparison['COMP_AVG_UNITS']) / comparison['COMP_AVG_UNITS'] * 100
comparison = comparison.sort_values(by=['DAYS_SINCE_RELEASE','STOREID'])
print comparison