CODEWITHSUNDEEP
pythonexception
CamelCamelCamel
CamelCamelCamel

Reputation: 5200

Python :: catching exceptions in order to traverse a list

Here's the code, part of a solution to problem 11 in Euler Project:

sum_d = 0
j = 0
while j < 20:
    i = 0
    while i < 20:
        try:
            sum_d = grid[j][i] * grid[j+1][i+1] * grid[j+2][i+2] * grid[j+3][i+3]
            if sum_d > result:
                result = sum_d
        except IndexError:
            pass
        i += 1
    j += 1

My question is whether catching those exceptions is considered a code smell? I can see that it will be tougher to debug such code (say, I accidentally looped over 19 items instead of 20, it will be harder to trace) but it is much more elegant then, say, coding i < (GRID_WIDTH - NUM_ITEMS_IN_PRODUCT) in the loop check.

P.S. I already solved the problem, I'm talking about the style of code

Upvotes: 0

Views: 178

Answers (2)

sverre
sverre

Reputation: 6919

You could at least make it

except IndexError:
    break

Anyway, yes I believe this is a code smell, and no it is not clearer than

for i in range(gridsize - num_items_in_product):

Upvotes: 1

Andr&#233; Laszlo
Andr&#233; Laszlo

Reputation: 15537

Spoiler: Here's part of my solution for problem 11.

for x in range(0,16):
    for y in range(0,16):
        prod = p[y][x] * p[y+1][x+1] * p[y+2][x+2] * p[y+3][x+3]
        m = max(m, prod)

Using exceptions instead of basic control structures is imho always a bad idea. This time you can get away with looping through the numbers 0..15!

Also, if you muliply stuff you get a product, not a sum. ;)

Upvotes: 7

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