python 返回一个列表中第二大的数方法

# 返回一个列表中第二大的数def second(ln):  max = 0  s = {}  for i in range(len(ln)):    flag = 0    for j in range(len(ln)):      if ln[i] >= ln[j] and i != j:        flag = flag + 1    s[i] = flag    if flag > max:      max = flag  print(s)  for i in s:    if s[i] == max - 1:      break  print(ln[i])second([1,2,7,4,5,6,8,5,3,3,9,9,10,11,5,3,20,19])