num = int(input()) p_l, n_l = [], [] num_array = list(map(int, input().split())) for i in num_array: if i < 0: n_l.append(i) elif i > 0: p_l.append(i) if len(p_l) == 0: # 处理无正数情况下的平均值 res = 0.0 else: avg = sum(p_l) / len(p_l) res = format(avg, &...