Counting the sum of a list in pandas dataframe column

I have a dataframe where column "lists" has lists:

l = ({'lists' : [[2,4,6],[8,10,12],[14,16,18]]})

df = pd.DataFrame(data = l)

I’ trying to add a new column that is the sum of the elements in these lists:

    lists           sum
0   [2, 4, 6]       12
1   [8, 10, 12]     30
2   [14, 16, 18]    48

So far I’ve tried:

df['sum'] = [sum(a) for a in zip(*df['lists'])]

but this sums the elements from all lists for example on row 0 the sum would be 2+8+14=24

How can I change the code to sum the elements inside one list?

>Solution :

Call sum in Series.apply:

df['sum'] = df['lists'].apply(sum)

Or list comprehension without zip:

df['sum'] = [sum(a) for a in df['lists']]

print (df)
          lists  sum
0     [2, 4, 6]   12
1   [8, 10, 12]   30
2  [14, 16, 18]   48