擅长:python、mysql、java
<p>你应该在for循环之外返回你的averageDict。如果它在for循环中,return语句将在第一次迭代之后返回,这是您不希望的。尝试如下。在</p>
<pre><code>def averageGrades(diction):
avgDict = {}
for k, v in diction.items():
# v is the list of grades for student k
avgDict[k] = sum(v)/ float(len(v))
return avgDict
print(averageGrades({"Shana": [100, 90, 80], "Jody": [100, 70, 80, 90, 100], "Mike": [100, 100, 20]}))
</code></pre>