L = [[1, 2, 3], [5, 3, 2], [7, 3, 2]]
for a in L:
for b in a:
x=b[0]
y=b[1]
z=b[2]
c=x*y*2+x*z*2+y*z*2
print c
你用b循环a,a是list,里面的值是int,每次循环只有一个int值
x=a[0]
y=a[1]
z=a[2]