Map & Reduce

def map_imp(f, l):
    res = []
    for x in l:
        res.append(f(x))
    return res

def map_rec(f, l):
    if (len(l) == 0):
        return []
    else:
        return [f(l[0])] + map_rec(f, l[1:])

def map_python(f, l):
    return list(map(f, l)) # convert to list

def filter_imp(f, l):
    res = []
    for x in l:
        if (f(x)):
            res.append(x)
    return res

def filter_rec(f, l):
    if (len(l) == 0):
        return []
    elif f(l[0]):
        return [l[0]] + filter_rec(f, l[1:])
    else:
        return filter_rec(f, l[1:])

def filter_python(f, l):
    return list(filter(f, l))

def sum_imp(f, l):
    res = 0
    for x in l:
        res += f(x)
    return res

def sum_rec(f, l):
    if (len(l) == 0):
        return 0
    else:
        return f(l[0]) + sum_rec(f, l[1:])

def reduce_imp(f, acc, l):
    res = acc
    for x in l:
        res = f(res, x)
    return res

def reduce_rec(f, acc, l):
    if (len(l) == 0):
        return acc
    else:
        return reduce_rec(f, f(acc, l[0]), l[1:])

def sum_reduce(l):
    return reduce_rec(lambda acc, x: x + acc, 0, l)

def any_reduce(l):
    return reduce_rec(lambda acc, x: x or acc, False, l)

def reverse_reduce(l):
    return reduce_rec(lambda acc, x: [x] + acc, [], l)

sages = [ ... ]

age = lambda s: s["death"] - s["birth"]

names = sorted(map_rec(lambda s: s["name"], sages))
names = sorted([s["name"] for s in sages])

most_ancient = sorted(sages, key=lambda s: s["birth"])[0]

most_longlived = sorted(sages, key=age, reverse=True)[0]

mean_age = sum(map_rec(age, sages)) / len(sages)