面试题:如何统计数组中出现次数最多的数据,按出现次数由大到小排序 这个排序看似简单,涉及到的基础知识点还是很多的,真正写起来并不容易
1.首先应该提出队列里面有多少个数据,做去重处理,去重最快的办法计算用到set集合了
a = ["a", "b", "a", "c", "a", "c", "b", "d", "e", "c", "a", "c"]
# set集合去重
duixiang = set(a) # 先去重,取出计数对象
print(duixiang)
2.然后计算每个对象再list里面出现的次数,可以保存为字典格式,一一对应
# 保存为dict,一一对应
d = {}
for i in duixiang:
d[i] = a.count(i)
1.保存为字典后,按字典的value值大小排序,这个才是本题的难点,由于dict是无序的,所以只能用list去排序,把dict的key和value保存为tuplue对象
# 对字典按value排序
a = sorted(d.items(), key=lambda x: x[1], reverse=True)
print(a)
# coding:utf-8
# 作者:上海-悠悠
a = ["a", "b", "a", "c", "a", "c", "b", "d", "e", "c", "a", "c"]
# set集合去重
duixiang = set(a) # 先去重,取出计数对象
# 保存为dict,一一对应
d = {}
for i in duixiang:
d[i] = a.count(i)
# 对字典按value排序
a = sorted(d.items(), key=lambda x: x[1], reverse=True)
print(a)