知识点

>>> [ x * x for  x  in range(10)]

[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

s=['sa','safa',56,77,'agsd']

if  isinstance(s,str):  #如果s[]列表是str 类型，则往下进行,如果不是则跳过

isinstance是判断类型是否错误

b1=[1,2,3,4]
b2=[2,3,4]
b3 = [val for val in b1 if val in b2]  #交集
b3 = [val for val in b1 if val not in b2]   #差集
print (b3)