1

Is it possible to create a grid like below? I didn't found anything in the forum.

#euler-project problem number 11
#In the 20 times 20 grid below,
#four numbers along a diagonal line have been marked in red.
#The product of these numbers is 26 times 63 times 78 times 14 = 1788696.
#What is the greatest product of four adjacent numbers in any direction
#(up, down, left, right, or diagonally) in the 20 times 20 grid?

import numpy

number = numpy.array([[08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08]
[49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00]
[81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65]
[52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 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 03 45 02 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 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21]
[24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72]
[21 36 23 09 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 03 80 04 62 16 14 09 53 56 92]
[16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57]
[86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58]
[19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40]
[04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66]
[88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69]
[04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36]
[20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16]
[20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54]
[01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48]])

EDIT no.1:

I found numpy-array now.

x = np.array([[1, 2, 3], [4, 5, 6]], np.int32)

Is there a way to do it without the commas?

EDIT no.2:

I also found a new problem. Python: Invalid Token Invalid token in number 08! :)

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11
  • Perhaps you should look at arrays. Commented Jan 21, 2010 at 20:35
  • 1
    I think you need to explain a bit more. Are you trying to print it like this? How are the sequences in each list defined? Commented Jan 21, 2010 at 20:35
  • I cant use the first part of my code. But I need an array. I get this with using numpy.array. Now I am looking for an other method without commas. Thanks in advance. Commented Jan 21, 2010 at 20:47
  • Where do the numbers come from? I suspect they would come as a string, which can be easily converted to a one-dimensional array of ints, then re-shaped into a 2D array of the correct rows x cols. Commented Jan 21, 2010 at 21:07
  • 1
    Why can't you use commas though? If you use vim, replacing the spaces with commas is as simple as :s/ /, /g (or you can use the search and replace in your editor of choice... Commented Jan 22, 2010 at 1:38

5 Answers 5

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3

You can define the numbers in a string and split it easily in row/columns:

nums = """\
1 2 3
4 5 6
7 8 9 10
"""
rows = [map(int, row.split()) for row in nums.splitlines()]
print rows      ##> [[1, 2, 3], [4, 5, 6], [7, 8, 9, 10]]
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Comments

2

Check out NumPy - specifically, the N-dimensional array object.

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1 Comment

What do you mean? KingRadical
2

Your code example won't compile unless you put commas between the list elements.

For example, this will compile:

value = [
         [ 1, 2, 3, 4],
         [ 5, 6, 7, 8],
         [ 9,10,11,12]
        ]

If you're interested in taking strings like you show, and parsing them into a list of lists (or numpy multi-dimensional array), or if you have a list of lists or numpy array and want to print them out like you describe, you can do that too with a clever couple of list comprehensions.

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3 Comments

Is there a way to do it without the commas?
Nope. NumPy needs a Python list type to convert to a NumPy array, which requires comma-delimited values.
Actually, there is a sort of round-about way of doing it without commas. Put the values in a space separated string, split at space, convert all list elements to ints/doubles and pass the resultant list to numpy.array. But why in the world anyone would want to do that, I have no idea...
0

What you have above does not work, e.g if pasted into a file and then run as a script, or pasted into the interpreter. I get: 

SyntaxError: invalid token

Again, I suspect that what you have done is paste text (a string) containing these characters. They are not integers, and you will get nowhere unless you realize that fact.

Edit: I see...we only get "invalid syntax" if we avoid the "invalid token" error caused by the "08"

>>> import numpy
>>> number = numpy.array([[08 02 22 97]])
  File "<stdin>", line 1
    number = numpy.array([[08 02 22 97]])
                            ^
SyntaxError: invalid token
>>> number = numpy.array([[18 12 22 97]])
  File "<stdin>", line 1
    number = numpy.array([[18 12 22 97]])
                               ^
SyntaxError: invalid syntax
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1 Comment

Actually, the 'invalid token' error is because python tries to parse 08 as an octal number, which is of course illegal...
0

As for parsing the actual data, and you don't want to read it from a file or use sensible methods, there is always this:

s = """[[08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08]
...etc
"""

s = s.replace("]", "").replace("[", "").split()

numbers = [int(x) for x in s]

Then you got a 1d array of numbers, which you can have fun with.

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