擅长:python、mysql、java
<pre><code>l= [['a', 10, 30], ['b', 34, 89], ['c', 40, 60],['d',30,20]]
sub1_avg = sum(n for _,n, _ in l)/float(len(l))
sub2_avg = sum(n for _,_, n in l)/float(len(l))
student_avgs = [{x[0]: sum(x[1:])//float((len(x)-1))} for x in l]
print "Sub1 avg - {}\nSub2 avg - {}\nstudent avg - {}".format(sub1_avg, sub2_avg, student_avgs)
</code></pre>
<p>样本输出</p>
^{pr2}$