python编程技巧

#1 随机序列[1,2,4,5,6,2,1,3,423,44,2...]中，找出出现次数最高的三个元素，他们出现的次数是多少
from random import randint
data = [randint(1,20) for x in range(30)]
c = dict.fromkeys(data,0)
for i in data:
    c[i]+=1

# 2使用collections来快速找出
from collections import Counter
c2 = Counter(data)
c2.most_common(3)  # 找出出现最多的key

# 3 使用re对对英文文章进行词频统计
import re
from collections import Counter
data = open(‘test.txt‘).read()
c3 = Counter(re.split(‘/W+‘,data))
c3.most_common(4)  # 统计出出现频率最高的4个单词

# 4 对字典里面的值根据value排序
from random import randint
d = {i:randint(60,100) for i in ‘abcdef‘}
data = sorted(d.items(),key = lamdba x: x[1])