#学生成绩records={'python':89,'C++':58,'Go':65,'SQL':49,'Java':78},找出大于各科目平均分的学科
records={'python':89,'C++':58,'Go':65,'math':49,'Java':78}
scores=records.values()
mean=sum(scores)/len(scores)
print({k:v for k,v in records.items() if v>mean}) # {'python': 89, 'Java': 78}