无法解决错误：“ int”对象不可下标

Question

I am trying to solve Project Euler's question 11 using Python 3.6.2. Whenever I try to run the code I have written, and it throws the error:

Traceback (most recent call last):
    File "E:/Euler11.py", line 6, in <module>
        product = data[i[j]]
TypeError: 'int' object is not subscriptable

the code being:

data = list([[8,2,22,97,38,15,00,40,00,75,4,5,7,78,52,12,50,77,91,8],[49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,00],[81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65],[52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,74,37,2,36,91],[22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80],[24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50],[32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70],[67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21],[24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72],[21,36,23,9,75,00,76,44,20,45,35,14,00,61,33,97,34,31,33,95],[78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92],[16,39,5,42,96,35,31,47,55,58,88,24,00,17,54,25,36,29,85,57],[86,56,00,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58],[19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40],[4,52,8,83,97,35,99,16,7,97,59,32,16,26,26,79,33,27,98,66],[88,36,68,87,58,62,20,75,3,46,33,67,46,55,12,32,63,93,53,69],[4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36],[20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16],[20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54],[1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48]])
maxProduct = 0
product = 0
for i in range(20):
    for j in range(16):
        product = data[i[j]]
        for k in range(1,4):
            product *= data[i[j+k]]
        if(product > maxProduct):
            maxProduct = product
print(maxProduct)

I'd greatly appreciate any help in explaining to me what I've done wrong.

Answer 1

You need to apply the subscriptions sequentially not nested. So you should use:

data[i][j]
data[i][j+k]

instead of:

data[i[j]]
data[i[j+k]]

Leading to the following (working) code:

maxProduct = 0
product = 0
for i in range(20):
    for j in range(16):
        product = data[i][j]
        for k in range(1,4):
            product *= data[i][j+k]
        if(product > maxProduct):
            maxProduct = product
print(maxProduct)

Answer 2

If you are in a 2D data structure, like your data and want to access it via for -loops, the right way would be

for i in range(height):
    for j in range(width):
        some operation using data[i][j]

In your case, you can determine the height and width with len . Also notice the data[i][j] . If you type data[i[j]] , Python will try to use the j th element of i as the index of data .

This will make your code run, but not solve the actual problem, because you'll have to check diagonals and verticals as well iirc.