'''
    python 高级笔记 如何统计序列中元素出现的次数
    来源:https://www.bilibili.com/video/BV1b5411s76z?p=4
'''

from random import randint
import timeit

list01 = [randint(1, 5) for _ in range(20)]
# 基础方案
# 初始字典,序列元素是key
dict01 = dict.fromkeys(list01, 0)
# 遍历序列 累加数量
for i in list01:
    dict01[i] += 1
print(dict01)

# 推导式方案
set01 = set(list01)
res = {k: list01.count(k) for k in set01}
print(res)

# Collections.counter 方案
from collections import Counter
print(Counter(list01))
# 前n个
print(Counter(list01).most_common(3))