'map'未得到的预期结果

Question

我希望得到以下结果，但我不能。有人能帮忙吗?(2, 4, 6, 8, 10, 12,[14、16、18],[20日22日24]]

A=[]
B=[]
C=[]
lst = [ [1,2,3], [4,5,6], [7,8,9], [10,11,12] ]  
for A in lst:
B = list(map(lambda x=B : x*2 for B in A , A)
C.append(B)
print(C)

Answer 1

lst = [ [1,2,3], [4,5,6], [7,8,9], [10,11,12] ]

如果你想保持你最初的方式:

C=[]
for A in lst:
B = list(map(lambda x : x*2 , A))
C.append(B)
print(C)

更简单的方法:

C=[]
for A in lst:
B = [x*2 for x in A]
C.append(B)
print(C)

甚至更简单，使用列表推导式:

C = [[x*2 for x in B] for B in lst]
print(C)