How to insert every string character to two dimensional array

I’ve made two dimensional array

rows, columns = (5, 4)
table = [["" for i in range(columns)] for j in range(rows)]

now I want to insert every string character to it

string = "aaa bb cccc d eee"

I want this output :
[[‘a’, ‘a’, ‘a’, ”], [‘b’, ‘b’, ”, ‘c’], [‘c’, ‘c’, ‘c’, ”], [‘d’, ”, ‘e’, ‘e’], [‘e’, ”, ”, ”]]

I tried something like this in many ways but it throws an error.

 for i in range(len(string)):
        table[columns][rows] = string[i]

>Solution :

for i in range(len(s)):
    lis[i // columns][i % columns] = s[i]
print(lis)