文件中最少的常用词

我有兴趣在文件中查找最不常见的文本.

from collections import Counter

# Load the file and extract the words
lines = open("mobydick.txt").readlines()
words = [ word for l in lines for word in l.rstrip().split() ]
print 'No of words in the file:', len(words)

# Use counter to get the counts
counts = Counter( words )

print 'Least common words:'
for word, count in sorted(counts.most_common()[:-3], key=lambda (word, count): (count, word), reverse=True):
    print '%s %s' % (word, count)

我如何限制只有3个单词.它打印出一堆.

你正在以错误的方式对列表进行切片.感受不同之处

print [1,2,3,4,5][:-3]
[1, 2]
print [1,2,3,4,5][-3:]
[3, 4, 5]