如何从单个列表中创建列表列表？

Question

I need to convert a list into a matrix form .I have written the the code below:

Grid=[]
count=0
for i in range(N):
    l=[]
    for j in range(N):
        l.append(grid[count])
        count+=1
    Grid.append(l)

here, grid is the input list and when I run it, I get below error.

Traceback (most recent call last):
  File "C:/Users/saikr/PycharmProjects/pythonprog/GlowingBacteria.py", line 80, in <module>
    ret=gb.findSolution(N,C,D,K,grid)
  File "C:/Users/saikr/PycharmProjects/pythonprog/GlowingBacteria.py", line 19, in findSolution
    l.append(grid[count])
IndexError: list index out of range

please help me solve this.

Answer 1

You can use another approach for creating matrix using python list.

  a = [[x] * m] * n

a is your desired matrix / multi-dimensional list.

m stands for the number of column and n stands for the number of row.

and the list [x] is the initializer of the list, you can use list comprehension here for initialize these value.

or

  N=5
  a = []
  for i in range(N):
      a.append([] * N)

do this for simply create an empty matrix of N x N.