astropy.table.Table: aggregrate over & combine multiple columns

astropy-table-aggregate

from astropy.table import Table

def average(col):
    # Manipulate multiple columns at once?
    return col.mean()

def average_pd(df):
    weight = df['weight']
    total = weight.sum()
    df['value'] *= weight / total
    df['value'] = df['value'].sum()
    df['weight'] = total  # for info; not necessary
    return df.iloc[0]  # ignore other rows: they are the same anyway


t = Table([['a', 'a', 'a', 'b', 'b', 'c'],
           [1, 2, 3, 4, 5, 6],
           [2, 2, 1, 2, 1, 1]],
          names=('name', 'value', 'weight'))
print(t)

group = t.group_by('name')
result = group.groups.aggregate(average)
print(result)

df = t.to_pandas()
result = df.groupby('name')[['value', 'weight']].apply(average_pd)
print(result)