Kinda newb-ish question

[ChocoboMog123]

What's wrong with line 8 in this code?
x=1
while 1==1:
x=x+1
y=range(1,x)
z=0
q=9
for count in y:
q=x%y
if q==0:
z=z+1
if z<1:
print x
It keeps giving me
Traceback (most recent call last):
File "C:\Python23\Pr ime Number.py", line 8, in -toplevel-
q=x%y
TypeError: unsupported operand type(s) for %: 'int' and 'list'

It's supposed to be a program to print out prime numbers.
If anyone knows of a program that does this or can write one, can you
show me the code? Thanks.

[BW Glitch]

Re: Kinda newb-ish question

ChocoboMog123 wrote:
[color=blue]
> What's wrong with line 8 in this code?
> x=1
> while 1==1:[/color]
I think it would be better as:
while True:[color=blue]
> x=x+1
> y=range(1,x)
> z=0
> q=9
> for count in y:
> q=x%y[/color]
It should be:
q=x%count[color=blue]
> if q==0:
> z=z+1
> if z<1:
> print x
> It keeps giving me
> Traceback (most recent call last):
> File "C:\Python23\Pr ime Number.py", line 8, in -toplevel-
> q=x%y
> TypeError: unsupported operand type(s) for %: 'int' and 'list'
>
> It's supposed to be a program to print out prime numbers.
> If anyone knows of a program that does this or can write one, can you
> show me the code? Thanks.[/color]

As it points out, y is a list.


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[Duncan Smith]

Re: Kinda newb-ish question


"ChocoboMog 123" <ChocoboMog123@ msn.com> wrote in message
news:5c27220b.0 312111650.7f0a1 28d@posting.goo gle.com...[color=blue]
> What's wrong with line 8 in this code?
> x=1
> while 1==1:
> x=x+1
> y=range(1,x)
> z=0
> q=9
> for count in y:
> q=x%y
> if q==0:
> z=z+1
> if z<1:
> print x
> It keeps giving me
> Traceback (most recent call last):
> File "C:\Python23\Pr ime Number.py", line 8, in -toplevel-
> q=x%y
> TypeError: unsupported operand type(s) for %: 'int' and 'list'
>[/color]

The clue is in the traceback. 'y' is a list. Presumably you meant q = x %
count.

Duncan

[Hans Nowak]

Re: Kinda newb-ish question

ChocoboMog123 wrote:[color=blue]
> What's wrong with line 8 in this code?
> x=1
> while 1==1:
> x=x+1
> y=range(1,x)
> z=0
> q=9
> for count in y:
> q=x%y
> if q==0:
> z=z+1
> if z<1:
> print x
> It keeps giving me
> Traceback (most recent call last):
> File "C:\Python23\Pr ime Number.py", line 8, in -toplevel-
> q=x%y
> TypeError: unsupported operand type(s) for %: 'int' and 'list'[/color]

The error message points out what's wrong with it... you're using the %
operator with an int (x) and a list (y), which is unsupported. You probably
mean something like x % count, although that doesn't make the algorithm work.

Quick tips: use range(2,x) rather than range(1,x), and x % count. An infinite
loop is probably not a good idea either. :-)

HTH,

--
Hans (hans@zephyrfal con.org)

http://zephyrfalcon.org/

[Mark Dufour]

Re: Kinda newb-ish question

On Friday 12 December 2003 01:50, ChocoboMog123 wrote:[color=blue]
> What's wrong with line 8 in this code?
> x=1
> while 1==1:
> x=x+1
> y=range(1,x)
> z=0
> q=9
> for count in y:
> q=x%y
> if q==0:
> z=z+1
> if z<1:
> print x
> It keeps giving me
> Traceback (most recent call last):
> File "C:\Python23\Pr ime Number.py", line 8, in -toplevel-
> q=x%y
> TypeError: unsupported operand type(s) for %: 'int' and 'list'
>
> It's supposed to be a program to print out prime numbers.
> If anyone knows of a program that does this or can write one, can you
> show me the code? Thanks.[/color]

Sure. The expression range(1,x) produces a list, not a number. So y is a list,
and x%y now tries to perform a modulo operation with a list as modulo number!

Instead of using z, you might also use a boolean, or True/False variable,
perhaps like this:

x=1

while 1:
x += 1
prime = True
for y in range(2,x):
if x%y == 0:
prime = False
break
if prime: print x

Notice the (2,x) instead of (1,x). You don't want to test for division by 1..

Of course, finding primes this way by trial division is a very slow method..
A simple optimization would be to only try numbers up to the square root of
x.


Mark Dufour.
--
"The employment agency has selected an immature and unproven software package
and its functionality is at the best close to Office 97," said Microsoft
representatives .

[David M. Wilson]

Re: Kinda newb-ish question

ChocoboMog123@m sn.com (ChocoboMog123) wrote...
[color=blue]
> It's supposed to be a program to print out prime numbers.
> If anyone knows of a program that does this or can write one, can you
> show me the code? Thanks.[/color]

Have you tried Google? Python code is lovely and verbose, and that
makes it fun to google for. Try: "def isPrime" +python

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/149148

http://mail.python.org/pipermail/python-list/2002-May/102160.html

Etc. :)


David.

[Harald Massa]

Re: Kinda newb-ish question

File "C:\Python23\Pr ime Number.py", line 8, in -toplevel-[color=blue][color=green]
>> q=x%y[/color][/color]
[color=blue]
> An infinite loop is probably not a good idea either. :-)[/color]

Why should it not be a good idea? Are there any ideas that the number of
primes is limited?


:-)

Harald

[ChocoboMog123]

Re: Kinda newb-ish question

Thanks for the help everyone. Worked out fine when I changed it.

[Hans Nowak]

Re: Kinda newb-ish question

Harald Massa wrote:[color=blue]
> File "C:\Python23\Pr ime Number.py", line 8, in -toplevel-
>[color=green][color=darkred]
>>> q=x%y[/color][/color]
>
>[color=green]
>>An infinite loop is probably not a good idea either. :-)[/color]
>
>
> Why should it not be a good idea? Are there any ideas that the number of
> primes is limited?
>
> :-)[/color]

:-) No, but the program will never finish, which doesn't make it very useful
except for staring at its output while eating tons of pretzels and listening to
The Orb.

--
Hans (hans@zephyrfal con.org)

http://zephyrfalcon.org/