Sum list based on function
Calculates the sum of a list, after mapping each element to a value using the provided function.
- Use
map()
withfn
to map each element to a value using the provided function. - Use
sum()
to return the sum of the values.
def sum_by(lst, fn): return sum(map(fn, lst)) sum_by([{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }], lambda v : v['n']) # 20