python基础练习 运行报错答:L1=['Hello','World',18,'Apple',None]L=[s.lower() if isinstance(s,str) else s for s in L1 ]print(L)['hello', 'world', 18, 'apple', None]或:L=[]L1=['Hello','World',18,'Apple',None]for s in L1: if isinstance(s,str): L.append(s.lower()) else...