每次写代码，LZ感觉还是得自己手敲一遍。。。一遍？一遍哪够？看着别人现成的代码觉得自己都能看的懂，等到自己上手解决自己任务的时候，才发现根本不是这么一回事。看了很多大神的博客，基本上都有一颗强大的内心，为啥？码了那么久的代码，结果一个bug就可能前功尽弃，从头再来，也是只能默默鼓励下自己：每天进步一点点！
"""Count words.""" def count_words(s, n): """Return the n most frequently occuring words in s.""" # TODO: Count the number of occurences of each word in s import re listOfTokens = re.split(r'\W*', s) # print (listOfTokens) ss = set(listOfTokens) # print (ss) bow = [0] * len(ss) ll = list(ss) for word in listOfTokens: if word in ss: bow[ll.index(word)] += 1 dd = {} for i in range(len(ss)): dd[ll[i]] = bow[i] # sort_dd = sorted(dd.items(), key = lambda asd:asd[1], reverse = True) sort_dd = sorted(dd.items(), key = lambda asd:(-asd[1], asd[0])) top_ll = dict(sort_dd[0:n]) top_n = top_ll.keys() # TODO: Return the top n most frequent words. return top_n def test_run(): """Test count_words() with some inputs.""" print (count_words("cat bat mat cat bat cat", 3)) print (count_words("betty bought a bit of butter but the butter was bitter", 3)) if __name__ == '__main__': test_run() test_run()代码量不大，但是对于python入门的新手任务来说还是有挑战的O(∩_∩)O
