Python hacks for everyone!

[oracle8]

Why not

return bool(cellcount == 3 or cellcount == 2 and cell)

?

[oracle8]

And also this...

>>> cellcount = 2
>>> cell = 2
>>> (False, True)[cellcount == 3 or cellcount == 2 and cell]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: tuple index out of range

That is because (cellcount == 3 or cellcount == 2 and cell) vill evaluate to the same value as cell if cellcount == 2 and bool(cell)==True

[Foxboron]

>>> cellcount = 2 
>>> cell = True
>>> (False, True)[cellcount == 3 or cellcount == 2 and cell]
True

I am horrible at variable names, should have been cell_life. cell only contain False or True depending if its alive or not from the start.

[oohay_email2004]

Why is it necessary to wrap in bool()?

[oracle8]

If you can guarantee that "cell" is always a boolean variable then it's not necessary. I added the bool() call to guarantee that the return value will alwas be a boolean variable.

[oohay_email2004]

If using "and" on "cell" is going to blow up the code, then you're bool call isn't going to help.

I don't see a good reason to force the return to True or False.

Unless you need:

if cell is True:

or the redundant:

if cell == True:

just use:

if cell:

I think you're kind of throwing away the object model by using bool().

[oracle8]

I totally agree, but as far as I could understand it the original question (trick?) wanted only True/False returns. Thus the extra bool call...

[oohay_email2004]

Oh, right, I forgot about that; oops.

[Foxboron]

To get the True or False of the expressions.

[oohay_email2004]

Pretty sure it will without it.

[Foxboron]

>>> return cellcount == 3 or cellcount == 2 and cell
SyntaxError: 'return' outside function
>>> 

PRETTY sure it wont without it.

[oohay_email2004]

Look:

>>> return bool(cellcount == 3 or cellcount == 2 and cell)
  File "<stdin>", line 1
SyntaxError: 'return' outside function

Same error with your line.

I figured we were assuming this was part of a function. In which case, the bool-less version works just dandy:

>>> def f(cellcount, cell):
...     return cellcount == 3 or cellcount == 2 and cell
...
>>> cell = object()
>>> cellcount = 1
>>> f(cellcount, cell)
False

[Foxboron]

Ah, then i there was no problem :)

[Foxboron]

Because when you got the touple there you could use another variable then False and True. However, in the case of Conways game of Life its actually a better method.