How do you evaluate a certain part of an array in Python?

Question

turns = [4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4]
turns.append([1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4])
turns.append([4, 6, 2, 8, 1, 9, 6, 5, 3, 7, 6, 8, 2, 4]) 
turns.append([0, 0, 26, 24, 3, 7, 5, 4, 25, 25, 21, 21, 21, 21])
turns.append([0, 0, 0, 0, 7, 3, 8, 2, 0, 0, 29, 29, 29, 29])
turns.append([0, 0, 0, 0, 26, 24, 0, 0, 0, 0, 0, 0, 0, 0])

arrayValue = turns[j][i]
    if arrayValue == turnCurrently:

Error Message:
Traceback (most recent call last):
  File "D:/a45d32f947055690c690d94f88/TicTacToe", line 183, in <module>
    arrayValue = turns[j][i]
TypeError: 'int' object is not subscriptable

My question is essentially, I want to test if turns[j][i] is equal to turnCurrently but I keep running into this subscriptable problem, I haven't been able to find this answered anywhere I think that this is a very important question. Thanks in advance, Richard

Are you sure you want turns in this form? You create a plain list in the beginning, then append new lists to it, so it looks almost like 2D, but not quite. — eumiro
– eumiro, Commented Jun 4, 2012 at 11:00

Óscar López · Accepted Answer · 2012-06-04 13:48:02Z

6

Try this for building a two-dimensional array (a "matrix") of turns:

turns = [[4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4]]
turns.append([1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4])
turns.append([4, 6, 2, 8, 1, 9, 6, 5, 3, 7, 6, 8, 2, 4]) 
turns.append([0, 0, 26, 24, 3, 7, 5, 4, 25, 25, 21, 21, 21, 21])
turns.append([0, 0, 0, 0, 7, 3, 8, 2, 0, 0, 29, 29, 29, 29])
turns.append([0, 0, 0, 0, 26, 24, 0, 0, 0, 0, 0, 0, 0, 0])

Or simply this:

turns = [[4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4],
         [1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4],
         [4, 6, 2, 8, 1, 9, 6, 5, 3, 7, 6, 8, 2, 4],
         [0, 0, 26, 24, 3, 7, 5, 4, 25, 25, 21, 21, 21, 21],
         [0, 0, 0, 0, 7, 3, 8, 2, 0, 0, 29, 29, 29, 29],
         [0, 0, 0, 0, 26, 24, 0, 0, 0, 0, 0, 0, 0, 0]]

As you can see, a matrix is nothing more than a list of lists. You weren't building a matrix in the first place - the first row has to be a list too.

edited Jun 4, 2012 at 13:48

answered Jun 4, 2012 at 11:00

Óscar López

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2 Comments

Rodda John Over a year ago

Thanks, this really helped, it fixed the problem, I would have never thought of the beginning being ints and the later pars being lists. THANKS SO MUCH!!

Óscar López Over a year ago

@user1434957 if this answer was helpful for you, please accept it as correct (click the check mark to its left)

poke · Accepted Answer · 2012-06-04 11:04:05Z

2

It often helps a lot to print out the content of your variables to see what it happening:

>>> turns
[4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4, [1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4], [0, 0, 26, 24, 3, 7, 5, 4, 25, 25, 21, 21, 21, 21], [0, 0, 0, 0, 7, 3, 8, 2, 0, 0, 29, 29, 29, 29], [0, 0, 0, 0, 26, 24, 0, 0, 0, 0, 0, 0, 0, 0]]

As you can see, the first few elements of that list are simple integers, but not a list of ints. So when j is small, it will select an int and try to apply [i] on it – which fails.

The solution in this case is to put the first elements into an extra list:

turns = [[4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4]]
turns.append( … )

Another way would be to initialize your list as an empty list, and append the first sub-list as well:

turns = []
turns.append([4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4])
turns.append( … )

answered Jun 4, 2012 at 11:04

poke

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1 Comment

Rodda John Over a year ago

Really helpful too, that identified the problem... THANKS

Emil Vikström · Accepted Answer · 2012-06-04 11:03:07Z

2

You array have a strange layout. The first 14 elements are integers, then follows a couple of other arrays.

So what you basically have is this:

[4, 6, 2, ..., 2, 4, [1, 1, 2, ...], [4, 6, ...], ...]

You may solve this by changing the first assignment to:

turns = [[4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4]]

answered Jun 4, 2012 at 11:03

Emil Vikström

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Comments

taskinoor · Accepted Answer · 2012-06-04 11:06:53Z

1

change turns = [4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4] to

turns = [[4, 6, 2, 8, 1, 9, 5, 5, 3, 7, 6, 8, 2, 4]]

edited Jun 4, 2012 at 11:06

taskinoor

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answered Jun 4, 2012 at 11:01

shiva

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1 Comment

shiva Over a year ago

if you think the answer is useful give an upvote on my answer and accept it

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