python - 在Python中使用for循环在嵌套列表中赋值

Question

我需要创建一个四层深度的嵌套列表。第四个层面，我需要系统地赋值。当第四级处于第一个循环的中间时，无论分配的值如何，我都会收到索引错误，如您在代码下方的输出中看到的那样。

    fourNest = [ [[[[[AA, BB, CC, DD]
      for AA in range(2)]
      for BB in range(3)]
      for CC in range(4)]    
      for DD in range(5)]]

    print fourNest   #this prints as expected and assignments work manually


    for AA in range(2):
        print "AA = ", AA
        for BB in range(3):
            print "   BB = ", BB
            for CC in range(4):
                print "      CC = ", CC
                for DD in range(5):


                    fourNest[AA][BB][CC][DD] = 1

                    print "          DD = ", DD,"  ", fourNest[AA][BB][CC][DD]

AA =  0BB =  0CC =  0DD =  0           1DD =  1           1DD =  2           1

Traceback (most recent call last):
  File "C:/Python27/forListCreateTest", line 21, in <module>
    fourNest[AA][BB][CC][DD] = 1
  IndexError: list assignment index out of range

Answer 1

LC 中的循环顺序需要颠倒。您还有一层额外的括号

fourNest = [[[[[AA, BB, CC, DD]
      for DD in range(5)]
      for CC in range(4)]    
      for BB in range(3)]
      for AA in range(2)]