擅长:python、mysql、java
<p>使用<code>collections.Counter</code>对象可以轻松完成此操作:</p>
<pre><code>import collections
infile = open(filename,'r')
grades = [g.strip() for g in infile.readlines()]
grade_counter = collections.Counter(grades)
for g, n in sorted(grade_counter.items()):
print n, "students got", g
</code></pre>