综合练习：词频统计

f = open(‘test.txt‘,‘r‘)
news = f.read()
f.close()

sep = ‘‘‘.,‘?!:"‘‘‘
exclude = {‘the‘,‘and‘,‘to‘,‘a‘,‘of‘,‘was‘,‘on‘,‘with‘,‘i‘,‘s‘,‘is‘,‘were‘,‘that‘,‘back‘,‘at‘,‘little‘,‘have‘}
for w in sep:
    news = news.replace(w,‘ ‘)

wordList = news.lower().split()
wordDict = {}
‘‘‘
for v in wordList:
    wordDict[v] = wordDict.get(v, 0)+1
for v in exclude
    del( wordDict[v])
‘‘‘

wordset = set(wordList) - exclude
for v in wordset:
    wordDict[v] = wordList.count(v)

dictList = list(wordDict.items())
dictList.sort(key=lambda x:x[1],reverse=True)
for i in range(20):
    print(dictList[i])

f = open(‘newscount.txt‘,‘a‘)
for i in range(25):
    f.write(dictList[i][0]+‘ ‘+str(dictList[i][1])+‘\n‘)