Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.

Dismiss

4 views

Skip to first unread message

Nov 3, 2005, 8:01:08 PM11/3/05

to

Another question: I am writing a sudoku solving program. The

'solving' part of is just multiple iterations. It will take random

numbers and keep switching it all around until a set of logic

statements has been met (ie; all numbers in a row are not equal to each

other) ... that's where my question comes in.

'solving' part of is just multiple iterations. It will take random

numbers and keep switching it all around until a set of logic

statements has been met (ie; all numbers in a row are not equal to each

other) ... that's where my question comes in.

Cellboard = my list for storing each row/column's data.

Rather than writing

cellboard[0] is not* (cellboard[1] and cellboard[2] and cellboard[3]

and cellboard[4] ... cellboard[8])

cellboard[1] is not (cellboard[0] and cellboard[2] and cellboard[3] and

cellboard[4] ... cellboard[8])

etc...

* should this be != ?

the above so that all the data in one row is not equal to each other,

is there something I can write to make it simpler? For example,

(cellboard[0] is not cellboard[1] is not ... cellboard[8]) only worked

for the numbers to the left and right of the cell - is there anyway I

can expand this to cover all numbers in a set range?

Nov 3, 2005, 9:00:32 PM11/3/05

to ale.of...@gmail.com, pytho...@python.org

On 3 Nov 2005 17:01:08 -0800, ale.of...@gmail.com

<ale.of...@gmail.com> wrote:

> the above so that all the data in one row is not equal to each other,

> is there something I can write to make it simpler? For example,

> (cellboard[0] is not cellboard[1] is not ... cellboard[8]) only worked

> for the numbers to the left and right of the cell - is there anyway I

> can expand this to cover all numbers in a set range?

<ale.of...@gmail.com> wrote:

> the above so that all the data in one row is not equal to each other,

> is there something I can write to make it simpler? For example,

> (cellboard[0] is not cellboard[1] is not ... cellboard[8]) only worked

> for the numbers to the left and right of the cell - is there anyway I

> can expand this to cover all numbers in a set range?

Python has an operator call 'in', which will allow you to do what you're after.

"1 in (1,2,3)" will be true

"4 in (1,2,3)" will be false

"not 1 in (1,2,3)" will be false

So you'd be after something along the lines of:

not cellboard[0] in (cellboard[1], ...., celboard[8]).

This seems quite tedious to write, maybe you should consider something

along the lines of using slicing:

not celboard[0] in cellboard[1:8]

I hope i have given you enough tools to do what you're trying to do.

--

Stephen Thorne

Development Engineer

Nov 3, 2005, 9:42:34 PM11/3/05

to

<ale.of...@gmail.com> wrote:

...

> Rather than writing

>

> cellboard[0] is not* (cellboard[1] and cellboard[2] and cellboard[3]

> and cellboard[4] ... cellboard[8])

> cellboard[1] is not (cellboard[0] and cellboard[2] and cellboard[3] and

> cellboard[4] ... cellboard[8])

...

> Rather than writing

>

> cellboard[0] is not* (cellboard[1] and cellboard[2] and cellboard[3]

> and cellboard[4] ... cellboard[8])

> cellboard[1] is not (cellboard[0] and cellboard[2] and cellboard[3] and

> cellboard[4] ... cellboard[8])

Urgh... the fastest way to check that a list of N numbers has no

duplicates is:

if len(set(thelist)) == len(thelist):

print 'no duplicates'

But if your purpose is to generate N random samples out of a population

of M, look at function random.sample (in module random in the Pythons

standard library) and you'll do even better!-)

Alex

Nov 3, 2005, 10:03:03 PM11/3/05

to

For the

not cellboard[0] in cellboard[1:8] (I knew about ranges/slicing using a

colon, can't believe I didn't think of that!)

line, will I have to write that out for each number?

So the line:

not cellboard in ((cellboard[1:8]) and (cellboard[9] and cellboard[18]

and cellboard[27] and cellboard[36] and cellboard[45] and cellboard[54]

and cellboard[63] and cellboard[72]) and (cellboard[1:2] and

cellboard[9:11] and cellboard[18:20]))

will cover all the logic requirements for the number in cell 0 (well,

row 1, column 1).

But will I have to copy + paste + edit that for all 81 cells? That

isn't complicated, just tedious - thanks though.

Nov 3, 2005, 10:08:05 PM11/3/05

to

UIAM if you have a list of items that are comparable and hashable, like integers,

you can make a set of the list, and duplicates will be eliminated in the set.

Therefore if the resulting set has the same number of members as the list it

was made from, you can conclude that the list contains no duplicates. E.g.,

>>> cellboard = range(8)

>>> cellboard

[0, 1, 2, 3, 4, 5, 6, 7]

>>> set(cellboard)

set([0, 1, 2, 3, 4, 5, 6, 7])

>>> len(set(cellboard))

8

>>> cellboard[2] = 7

>>> cellboard

[0, 1, 7, 3, 4, 5, 6, 7]

>>> set(cellboard)

set([0, 1, 3, 4, 5, 6, 7])

>>> len(set(cellboard))

7

So the test would be

>>> len(set(cellboard))==len(cellboard)

False

And after repairing the list to uniqueness of elements:

>>> cellboard[2] = 2

>>> len(set(cellboard))==len(cellboard)

True

HTH

Regards,

Bengt Richter

Nov 4, 2005, 7:30:44 AM11/4/05

to

How do I 'define' set? Is there something to include (like import

random)?

random)?

while (choice == 3) and len(set(cellboard[0:8]))==len(cellboard[0:8]):

# DEFINE TWO RANDOM VARIABLES (ONE FOR ARRAY, ONE FOR NUMBER

VALUE)

solvingrandom = random.randint(1,9)

cellboardrandom = random.randint(0,8)

set(cellboard[0:8])

# CHECK TO MAKE SURE THE RANDOMLY ASSIGNED CELL DOES NOT HAVE A

VALUE

if (cellboard[cellboardrandom] is not ('1' or '2' or '3' or '4'

or '5' or '6' or '7' or '8' or '9')):

cellboard[cellboardrandom] = solvingrandom

The above is my code (right now it will only work for the first row's

numbers). Anything else I need to add?

Nov 4, 2005, 8:16:26 AM11/4/05

to

ale.of...@gmail.com wrote:

> How do I 'define' set? Is there something to include (like import

> random)?

>

set is a built-in type in Python 2.4> How do I 'define' set? Is there something to include (like import

> random)?

>

If you use 2.3 you can use the sets module with "import sets"

> while (choice == 3) and len(set(cellboard[0:8]))==len(cellboard[0:8]):

> # DEFINE TWO RANDOM VARIABLES (ONE FOR ARRAY, ONE FOR NUMBER

> VALUE)

> solvingrandom = random.randint(1,9)

> cellboardrandom = random.randint(0,8)

> set(cellboard[0:8])

>

> # CHECK TO MAKE SURE THE RANDOMLY ASSIGNED CELL DOES NOT HAVE A

> VALUE

> if (cellboard[cellboardrandom] is not ('1' or '2' or '3' or '4'

> or '5' or '6' or '7' or '8' or '9')):

> cellboard[cellboardrandom] = solvingrandom

>

> The above is my code (right now it will only work for the first row's

> numbers). Anything else I need to add?

>

Simplify your code a bit:

'2' is not ('1' or '2' or '3' or '4' or '5' or '6' or '7' or '8' or '9')

evaluates to True

'1' is not ('1' or '2' or '3' or '4' or '5' or '6' or '7' or '8' or '9')

evaluates to False

Somehow I do not believe you want that behavipur.

If cellboard contains characters, you could use:

if (cellboard[cellboardrandom] not in '123456789')

for integers, the following should work:

if not (1 <= cellboard[cellboardrandom] <= 9)

Using None to code empty cells, you could even have:

if (cellboard[cellboardrandom] is None)

Nov 4, 2005, 11:03:01 AM11/4/05

to

> will I have to write that out for each number?

Not if you know how to use the 'for' statement. It will allow you to

iterate through the rows or columns or whatnot.

0 new messages

Search

Clear search

Close search

Google apps

Main menu